Science topic
Air - Science topic
The mixture of gases present in the earth's atmosphere consisting of oxygen, nitrogen, carbon dioxide, and small amounts of other gases.
Questions related to Air
For Finned plate single pass solar air heater (1.2 m length) under forced air convection, What is relationship of temperature difference between the passing air (Ta) and the absorbing plate surface (Tp) as a function of the length of the solar air heater (L) ?
(Tp − Ta) Will it increase or decrease with the length of the air path through the solar air heater
CFRP panel is fabricated and cure for 24 hours at atmospheric condition. now I want to know that, Is further curing can be done on hot air oven? and how we decide the temperature limit?
I want to ask you that if we can analyze the dust particles present in air passing through a filter such as HEPA filter in ansys
Sir basically we want to know how fast the filter gets dirty mean blocked by dust particles.
I want that the air contains dust and some other particles and it is passed through a series of filter each of different pores size.Can this be done in ansys.
Assume vehicle is off and windows are closed. Can enough fresh air enter through door seals or fresh air intake in cowling to provide enough oxygen. Assume one person is in car.
Hi, I'm looking for chemical monitoring databases for soil, groundwater, sediment, drinking water, air and surface water in Spain. It seems that there are many federal and regional government and institutional sources that might be relevant but there are so many of them I don't know where to begin searching. Is there anybody out there familiar with Spain that can point me in the right direction?
Thanks
David
I am currently working on cultivation of Chlorella vulgaris. I am just curious to know what happens. Thank you in advance.
Want some idea related better suspension system between spring damper/ leaf spring in HGV's.
Numerically as well as Analytically.
On which parameter we decide to compare the results of both suspension system.
Pulling moisture from the air There are condensers that can pull moisture from the air. I need other than
I'm trying to get some good microscopic photographs of insect genitalia for my research work but I'm having trouble removing the air bubbles that comes inside the genitalia, no matter how cautious I'm.
Suggestions are appreciated.
Dear colleagues, we are looking for some inputs related to UV/Ozone lamps used for applications in indoor vertical farming. We understand that UV and Ozone are not so good for growing, but we exploring avenues related to the sterilization of the room and air in the room.
Every little helps
The reasons that lead to concrete cracking are many, including (high temperatures, pouring concrete in large areas, or as a result of high loads, or problems in the components of the mixture..) so I am looking for materials that enter the concrete industry that can treat cracks on their own.
Is the water absorption test is used for evaluating air bubble content or void content of a composite?
I need assistance on Environmental Attributes ( that means any and all claims, credits, benefits, emissions reductions, offsets, and allowances, howsoever entitled, resulting from the avoidance of the emission of any gas, chemical, or other substance to the air, soil or water)
I have a 2D simulation of the capillary rise between two identical parallel plates. I am using the Phase Field method and the software COMSOL Multiphysics. For validation I am using this paper: https://onlinelibrary.wiley.com/doi/epdf/10.1002/ceat.201500089
My problems are:
1) I don't get the capillary height from the paper
2) The water/air interface won't settle down to an equilibrium. Even after 15 seconds it still moves
Did anyone ever had the same problem and knows how to fix it?
Thanks a lot.
I have a container of volume 15 liters . It is connected to another container having volume 5 liters with the help of Stainless steel pipe and solenoid valve is installed in the pipe to prevent flow of air from 15 liters cont. to 5 liters container. vacuum is in 5 L container and valve is open how much air from 15 liters container flow to 5 liters container. Pressure in 15 Liters container is reduced to 660 mmHg from 760 mmHg
According to ASHRAE the values of tb and td for Atlantic, I want their values according to cities or latitude and longitude
Thanks
Hello Friends, I have a question that is stated in the title. I saw many papers trying to introduce moisture in a system by bubbling the air through it first. How much exactly moisture is introduced to the system using this way? Is there scientific reasoning how air is carrying water molecules with it?
Does anyone can help me to find the mean or expected number of infectious viral doses released in the environment during breathing by a infected subjet
I write a spreadsheet for calculating the time trend of the infecting viral dose in a mechanically ventilated environment, according to the number of air changes.
The calculation highlights the importance of the number of air changes/hour.
Sto cercando aiuto per sapere il numero medio o atteso di dosi virali infettanti emesse nell'ambiente durante la respirazione da un soggetto infetto.
Ho scritto un foglio elettronico per il calcolo dell'andamento nel tempo della dose virale infettante dentro un ambiente ventilato meccanicamente, in funzione del numero dei ricambi di aria.
Il calcolo evidenzia l'importanza del numero di ricambi dell'aria per ora.
The problem is a transient cooling of a hot surface using a confined impinging air jet. A 2D impinging jet is directed onto a segment of heat source of length L and set at constant "Heat flux". I am facing a problem in the results of simulation. The problem is that for high values of L, the cold air becomes hotter than the heat source when time goes on!! Can anybody faced such a problem in Comsol?
I need to make thin film of CsSnI3 for solar cell application. Kindly suggest me method and research paper which help me to deposit thin film of CsSnI3 without requirement glove box. I want to deposit thin film at ambient condition.
Thanks
Hello all,
I am trying to model CO2 being dissolved in a bubble column filled with water. For mass transfer definitions, I need to define two phases: for instance, liquid and gas, where the liquid phase includes h2o (l) and some other species, and the gaseous phase includes CO2 and air. Fluent only allows me to define material type as "solid", "fluid' or "mixture". I define one "mixture template" in which I add CO2, Air, and H2O (l), but I cannot add another "mixture template" in which I could define similar or different species. I define a dummy phase for CO2, but inside this dummy phase I cannot define a species under "Multiphase model -> Phase Interaction -> Mass -> Mass transfer -> "from phase" and 'species" to 'dummy phase" and "species".
Can anyone please help me with that? I want to do this to instruct Fluent to have mass transfer from CO2 in one phase to CO2 in another phase (dissolving)?
Thank you!
Hello guys,
I would like to know whether I could simulate three phases or three liquids in the VOF model in Ansys Fluent. If we can, then how can we do it?
One is Air and the other two liquids are polymers. Any suggestions are highly appreciated!
Thank you
Rajesh
Eulerian Multiphase simulation, the simulation is simple a 2D tube filled with water (primary phase) and 5mm glass bead (2ndphase), the inlet boundary was set from bottom of the tube with constant velocity of 0.01 m/s and environment pressure at top of the tube, this is a simple fluidized bed setup. The illustration of the initial condition of simulation setup are shown in the attached file as "Illustration of Initial Model"
The setup detail of the model is shown below:
Simulation type : Eulerian Multiphase with VOF
Analysis type : Transient Implicit
Time Step : 0.001 s
Total Time : 60 second
Glass bead phase : granular 2ndphase with VOF phase localized discretization of 0 (because in future I need to include air bubble into the simulation, so for glass bead 2nd phase, I use VOF phase localized discretization of 0 which is similar to diffused phase setting)
Glass bead density : 2230kg/m3 (denser than water)
Glass bead diameter : 5mm
Drag Model : Wen Yu
Maximum Packing limit : 0.6
Initial volume fraction of glass bead : 0.6 (same as packing limit)
I found out if the inlet velocity is too low (let say 0.01m/s) and cannot achieve minimum fluidized bed (mean the glass bead fluidized bed is stationary at the bottom of the column), the model become unstable, the residual value will have sudden jump and failed to converge in the interval of around every 30 time steps (0.03 second), the residual plot are shown in the attachment "Residual Plot"
When the velocity is set to 0.04m/s and above (over the minimum fluidized velocity), the fluidized bed starts to increase in height, the volume fraction starts to reduce below 0.6, and the simulation do not have convergence problem anymore.
I suspect this phenomenon is due to the volume fraction of 2nd granular phase is close to 0.6 (maximum packing limit) and the 2nd phase is unstable.
In future I will migrate this fluidized bed from this simple tube to a stirred tank. I believe after the stirred tank flow achieved steady state (around 60 second), the velocity in this fluidized bed will over the minimum fluidized velocity and no convergence problem. However, the real case is, just after the stirrer of the tank start to rotate, the velocity in the fluidized bed is still close to zero, it will take time for that region to achieved certain velocity, it will unstable/fail to converge before the tank achieved steady state.
Anyone have idea of how to stabilize the granular 2nd phase (fluidized bed) even with very low inlet velocity?
Thank you for your time.
I want to calculate the pressure applied to a balloon when it is inflated by air.
Is it possible using stoney equation as set the thickness of substrate as radius of a balloon?
Or is there other way to calculate it?
I am using an air sensitive solid compound in my experiment. the solid compound is sealed and labelled "air sensitive, Argon charged". I want to know
1. how to insert it in the flask without making air contact?
2. how to reseal the compound which is left?
the compound is terephthaldicarboxaldehyde. case number CAS : 623-27-8
Is there any research prospect to improve the efficiency of heat pumps through the different coupling modes of solar energy and air source heat pumps?
I have shadowgraphs of plasma filament formed in air by focusing a femtosecond laser and I am trying to solve for refractive index change in the region using the shadowgraph. The contrast value at each pixel is a source term for 2D-Poisson equation.
I can apply the Dirichlet boundary condition at the top and bottom of the image. But the left and right corners contain sections modulated by the filament.
What type of boundary conditions should I use in this case?
The nodal seismometer(ZLAND) with a sampling frequency of 1000 Hz is buried in a shallow hole and the upper of ZLAND is exposed to the air. The seismic signal is excited by manual hammering at a distance of 20 m. Can both air waves and seismic waves be collected by Zland?
'A hospital ventilator is fed by an oxygen supply at 177 g/s mixed with ambient air, density 1.295 kg/m3, at a rate of 0.69 m3/s. The gas mixture is humidified by the addition of 0.161 kg/s of water. Calculate the total mass flow of fluid supplied by the ventilator in kg/s, to 3 d.p.'
Hello, I am a First Year at my University taking Engineering, and need some help understanding this question.
The answer to it is 1.232kg/s
Thank you to anyone who can help!
When I read papers about health effects of ambient air polluatants, I meet a question.
We have the data on ambient PM2.5 and PM10 concentrations from air monitors, how to estimate the concentration of ambient coarse particular matter (PM2.5-10)?
I prepared perovskite solar cells (Glass/FTO/compact TiO2/mesoporous TiO2/Perovskite/spiro/Gold) inside dry air glove box. The best obtained efficiency was 6.6% which is very low. The resistance of compact TiO2 and mesoporous TiO2 layers is very high (20 and 700 KΩ). I prepared compact TiO2 and mesoporous TiO2 layers by spray pyrolysis and spin coating methods, respectively. How can I solve the problem of the high resistance of compact TiO2 and mesoporous TiO2 layers in perovskite solar cells?
If θ = θ(z) denotes the potential temperature of a parcel of atmospheric air at level z above the surface, and d/dz denotes the derivative with respect to z, when can one consider that θ dθ/dz = constant (with z) ?
What would be the physical significance of this constancy?
Dear Dan Dobrovolschi
The estimate of a constant for your equation that I have assumed is based on the graph from a paper:
Hello,
I'm about to start a project about designing an optimal heating algorithm for outdoor pools and hot tubs. The algorithm we are aiming for should take into consideration not only the current water and air temperature, relative humidity, pool surface and volume but also the predicted temperature in the next 24h in order to minimize the necessary heating needed to attain and keep a given water temperature (ex: 27 deg) in a certain time (like in 6h when people will bathe at 13h00).
I would be looking for the following two kind of advice:
1) Papers or reports about predictive control design methodology on energy efficiency
What appears different with our project is the fact that the required heating will be influenced by much later acquired solar heat during the day. How best to take such long term effect into account?
2) Tutorials and first hand experience with OpenFoam or TRNSYS on this kind of modeling problem:
I have a strong mathematical and programming background but no experience with either software or FEM/CFD. Any suggestion about which tool might be easier to model and experiment with for this problem?
Regards,
Bruno
Hi everyone. Does anyone know how to model an air to water reversible heat pump to feed the heated and cooled floor (radiant surface) in Designbuilder detailed HVAC? I can find air to water heat pump only for heating and it is not possible to make it reversible.
Thank you in advance.
Greetings !
respected dear i am working to a novel design of wet cooling tower for my final year project as B.E requirement.
I am confused about that if i use cars radiator instate of air to Air tube heat exchanger at the top of the tower ?
kindly help me and guide me , what will be results if i use car's radiator instate of air to air tube heat exchanger ? it would increase the efficiency of wet cooling tower or may decrease ?
I would like to perform high temperature oxidation experiments in air. If I understand correctly, the amount of water vapor in the air has a great influence on the oxide scale growth.
Can anyone give me tips on how to determine or at least approximate the proportion of water in the air at up to 1200 °C?
Hi!
I'm studying on the mechanism of one reaction.
I think formaldehyde is generated as byproducts during the reaction
So, Identification of formaldehyde is a strong proof for mechanism that I suggested.
The reaction is processed in solvent in septum cuvette.
Formaldehyde has a very low b.p(-19 °C), so even if it is generated, it will fly into the air.
I heard that LCMS has a problem to ionize formaldehyde molecule.
FTIR is also has a problem that one of the products has a C=O group.
So I can't know whether C=O group is from formaldehyde or one of the products.
How can I identify the presence of formaldehyde?
Dear Young Cheol Ki ,
Two colorimetric tests comes to my mind.
The first is "Le Rosen test" which I illustrate in one of the drawing with toluene. For your purpose, I think phenol is more adapted as soluble in water. A typical procedure should be preparing a test tube containing water, sulfuric acid and phenol. Via a canule, you bubble the gaz formed in your reaction into this solution. A red colour should appear in the presence of formaldehyde when forming the p-quinoïdal adduct as illustrated.
A second test could be the formation of a dihydropyridine compound (deep yellow and fluorescent). You can bubble your reaction into a hot vial (60-80°C) containing ammonium acetate (~ 2.5 g for 10 mL of water and 0.3 mL of glacial acetic acid and an amount of acetylacetone).
I hope this could help you !
H2 : 16.16 %
O2 : 0.03 %
N2 : 49.98 %
CH4 : 1.83 %
CO : 17.15 %
CO2 : 14.83 %
( All % are on volume basis)
Hi
How can you calculate the concentration of benzene in air in mg/m3 surrounding soil if you know the concentration in the soil in mg/kg. Was thinking of using the approximation that the soil is water. The air is in a closed cylindrical - it is a hole in a soil with a lid on top - so the air is surrounded by soil and need to know the concentration of benzene in that air space in mg/m3 (ppm) when the concentration of benzene is 0,2 mg/kg in the surrounding soil.
Thank you!
In comparison with a flat plate solar air collector and solar air collector with 10-meter tube. Which one should be taken for air velocity measurement? Inlet air velocity, outlet air velocity, average, Ashrea standard or ....
Pressure loss is 275 Pa in tube collector.
How can I measure with hotwire? How and where should I put it?
Thanks.
I want to know, why the air bubble mixes with a polymer. Although we thoroughly dried the PET chips, but see a lot of air-bubble at the outlet with molten PET before the spinning plate. What is the possible reason for this?
I'll soon be working on a project that involves nanoparticles which need to be under anoxic conditions. My collaborators are preparing the samples in an inert glovebox at another institution and sending them to me. The question is, how do I load them into the TEM holder without exposing them to air? I don't have access to a glovebox, but is there a way to jerry-rig a system that would allow me to minimize the time the samples are exposed to air? A colleague mentioned using some kind of container that I could fill with nitrogen, either from compressed N2 or liquid N2, but I'm not sure what kind of container I might use for that purpose. We don't have a vacuum holder, so they will be exposed to atmosphere when I load the actual sample holder into the microscope, but I'm looking to at least try and avoid exposing them during the actual sample loading. Any tips?
hi.
I have a problem in my simulation work. I use flow-3d for simulating a surface vortex with an air core in a pipe-tank system. I have been successful simulating the vortex with 1cm mesh size, but I haven't been able to see the air core. Due to this problem I had to had to use finer mesh with size of 0.6cm.
When using finer mesh ,my streamlines of the near surface particles change dramatically in comparison with the streamlines I had when using coarser mesh with 1cm mesh cell size.
In coarser mesh my streamlines are strongly sucked and driven into my pipe but when i reduce my mesh cell to 0.6cm, with exactly the same setup my streamline suddenly get shorter and incomplete. It seems that after changing the mesh size the flow of water in to the pipe is not enough strong to create the enough suction for near surface particles of water and due to this there i see no air entrainment afterward.
I will upload the photos of my streamlines in both conditions, I'll be so delightful if anyone can tell what is the cause of this problem I have and how I can solve it?
I want to make chitosan -composite sponge without using a freeze drier. Is air dried fabrication method of foam possible for chitosan?
For making chitosan sponge I found in literature that almost all researchers made chitosan sponge by using only freeze drier. Some of them have used pore forming chemicals to get uniform pores but after using that chemicals, they have used freeze drying. I want to know such process where chitosan sponge is made by other processes while NOT using freeze drier once. Means i need an alternative sponge fabrication method by completely omitting the use of freeze drier.
Thanks.
I want to heat activated carbon in a furnace, under normal air condition.
I am using Abaqus for a project where I am modeling air propagation through buildings. I am using a 3D Eulerian domain (Eulerian elements) to represent air.
I have also been trying to use adaptive mesh refinement for the Eulerian domain by adding the below commands to the input file:
*ADAPTIVE MESH REFINEMENT, ratio=2.0, ELSET=adaptive_set
*ADAPTIVE MESH REFINEMENT,
PRESS, 0.1, 0.01
However, I am getting the below error:
ADAPTIVEMESHREFINEMENT Invalid parameter: 0.1. The parameter may be misspelled, obsolete, or invalid.
Does anyone know how to use the adaptive mesh refinement in Abaqus?
Thank you
I want to simulate the heat pump (air source) with unite storage thermal Tank but I get the following msg:
''350 : Unable to open the file associated with an
ASSIGNED logical unit number.
Please check the ASSIGN statement and make sure
that the file exists at the specified location''
and I want to,know also how can I creat a file
external if necessary
thank you
Hello,
I am working on a precipitation analysis and have data for two rain gauges. I also have air temperature. What is the best way to determine precipitation type? What is a good temperature to assume anything above is rain and anything below is snow? I assume there is also an uncertainty range (-1C to 4C?)?
Any help would be much appreciated!
Im thinking about trying to synthesize some poly beta amino esters, however Im not sure if the chemistry is air sensitive or just water sensitive. The reaction is a polymerization reaction between amines and acrylates via Michael addition.
Also was wondering if you are supposed to remove the inhibitors from the monomers using inhibitor removal resin or keep them in, the materials and methods sections of these PBAE synthesis papers dont mention it, but it seems like something that would be necessary.
My final goal is to find a multiple linear regression to predict actual evapotranspiration, ET (response variable) using remotely sensed land surface temperature and ground-observed air temperature (explanatory variable). All are raster (.tif) format. They are 5-year dataset with the same extent and temporal (16days) and spatial (500m by 500m) resolution.
I was trying to find some ways for spatial regression, raster regression, spatial statistics, etc. but I fail to one that can be applicable to my case. Most ways that I found didn't handle the time series as two explanatory variable at the same time.
Has there been anyone who tried or applied this type of approaches?
I am currently working on a gear problem where the gear assembly has to be kept inside the air domain. To make the gear rotate I have to give assembly in the geometry section and to put the model in an air domain and to make the air flow over the geometry surface I have to give Union in the geometry section. I don't know how to make both happen simultaneously. I have been trying to solve this problem over a few months But, not been able to find a solution. I need your help with this issue.
By given inlet and outlet condition of Air Preheater I need to design Air Preheater By using formula Q=UA(LMTD) the unknown are A and U. for finding the A how we calculate U.
Since the air will be pumped from the chamber to perform a GC to determine the CO2 concentration, we will need to add "dry" air to the chamber to maintain the pressure. However, this dry air may dry out the soil. So how do we maintain a field capacity of 60%?
Hi there,
I am looking for tips and tricks on how to model a cooling coil
I want to know, the estimated extract can one can get for each extraction in terms of percentage over weight of air dried holy basil leaves, suppose I'm using acetone as a solvent for extraction. suppose I'm using simple distillation as a process of extraction.
note: the question is about % of extract holy basil yield, not essential oils, but including essential oils as an extract.
My current research is dealing with creating rough copper surfaces with certain attributes. Because the performance of the copper substrate is reliant on this specific surface topography, I am looking to determine how these features may change over time in different environments. Of particular interest is the effect of a biological environment, as well as the effect of air at room temperature. I have already done some research about the effect of a biological environment on copper surfaces and have concluded that in general corrosion occurs, but am unsure how a roughened surface would impact this effect. Any ideas or references is greatly appreciated.
Hi all,
I found our group has an "old" XRPD humidity chamber connected to some moisture-control system. The moisture-control system has a sensor that detects the humidity of the air it sends to the chamber, but we would like to be able to check the humidity in the chamber as well to be sure at which RH we run our XRPD.
Does any of you know if/how this is usually done? Is there a reference substance that one can use?
Thanks in advance for your help!
/V
Greeting
I would appreciate you if you help me to find the answer of this question:
however ambient air is cooler than engine coolant but Why it is not preferred instead of engine's coolant in recovering engine waste heat by TEMs (Thermoelectric materials ).
Hi, I have a tube exposed from the top to solar radiation and contains air inside it, the tube is closed from both ends, I want to calculate the heat transferred from the upper side to the lower side?
I am analyzing VOCs in the air and have a question about choosing a column for good separation of VOCs. I use GC-FID and inject 1 uL (split ratio: 1:10).
in humidification room , hot air enter the room from the bottom and water droplet enter the room from the top , humid air leave the room from the top and brine water leave the room from the bottom , then the humid air condense in the dehumidification room
I need to make a TCEP (Tris(2-carboxyethyl)phosphine hydrochloride) stock solution for molecular purposes (immobilization DNA on Gold nanoparticle).
I want to know, Does TCEP powder is sensitive to air (on the pack written: air-sensitive packed under argon)?
should I use a glovebox?
I am using the Discrete Ordinate Radiation Model and Solar Loading to incident light rays on the top of the glass plate. My model has a glass plate of 3 mm thickness, and below that, the air is flowing, and there is also an absorber plate of 1mm thickness. The walls are insulated to avoid any losses.
However, the question remains, what temperature "glass" should have with respect to the air at the "outlet"? Should it be higher or lower?
Please, provide a logical explanation along with the answer.
Thanks.
I wanted to buy an incubator in which we will be maintaining neuronal as well as cancer cells. With advancement in technologies, i was wondering whether air or water jacketed incubator is best for academic lab purposes? All your inputs are much appreciated. Thanks
I have two questions. I would appreciate it if anyone can help me with these questions:
We have a raceway pond in which O2 is continuously produced due to the presence of algae. We know that the water can dissolve O2 up to its solubility which I think is 40 mg/L (under normal conditions). My question is that what would happen after the water is saturated with O2? What is the fate of O2 that is produced after the saturation point? Do they rise up to the surface and then diffuse into the air? Is there any chance of bubble formation in this case?
And the second question is: If the water is saturated with O2, does it prevent available CO2 in the air to be absorbed into the water? What is the reaction between the O2 and CO2 in this case?
I have the the constants for air density, radius of pipe, Radius of the propeller, and the rpm of the propeller. I need to find the inflow air velocity and mass flow rate of the air and the outflow mass flow rate and velocity of the air from the propeller. is there a formula, method or theory for this?
One of Nikola Tesla's greatest inventions is the blade-less turbine, referred to as 'Tesla turbine'. In the case that the driving fluid is air, I am interested on how air constituents (principally Nitrogen and Oxygen) are radially segregated between the rotating discs. Any suggestions?
Hello Everyone,
Could anyone suggest the best place to publish feasibility studies and popular science articles? In Air Buoyancy Engines I demonstrate feasibility of updraft towers or air balloon engines generating energy with 12% efficiency from a 33 C heat source. The main credit for balloon engines belongs to Dr. Ion Edmonds. In Feasibility of Extremely Heavy Lift Hot Air Balloons and Airships I demonstrate feasibility of airships using hot air as lifting gas. For insulated high mass airships, thermal power requirement is proportional to the cubic root of mass. In Harvesting Jet Stream Wind Power by Turbines on Moored Airships I demonstrate that high altitude wind power can be economically harvested by the aforementioned hot air airships.
Thank You
Are there any climatological trials to increase the C02 concentration in rates like of 300 ppm, 400 ppm, 500 ppm, 1000 ppm, 10.000 ppm of the air in volumes sizes like of plastic balloons, round-bottom flasks glass or in glass houses and coincidentally observing and measuring the air temperature during variable day sunshine irradiation and how temperature behaves or rises really - also in presence of different rates of earth like materials like water, soil and plants like on earth surface conditions and also with only the presence of air?
Ad hoc I could not find any results.
Hello everyone,
I have a serious problem with coating the Pd/C catalyst uniformly on the glassy carbon.
I prepared the Pd/C ink by adding 20 mg of Pd/C into 9 mL of DI water. Then I sonicated it for 10 mins. I added 1 mL of IPA into the mixture and sonicated for another 10mins. I pipetted 5 uL of the ink on the center of glassy carbon (Diameter=3mm) and dried it in the air. To avoid any dusk from the air, I used a biker to cover the glass carbon. But I can't get a uniform layer of Pd/C catalyst on glassy carbon. Here is the picture of the Pd/C film. Can anyone help me with this problem?
Thanks,
Jay
It is required to determine the total area to operate an air conditioner that operates on solar energy and partially operate the air conditioner when the power is cut off.
So I have been performing stereotaxic surgery on VGAT-Cre mice. the virus I am injecting is a double floxed hm4d Gi - mCherry reporter. Whenever I finish infusing 250 nL of the virus into the mouse brain, I like to check if the needle is clogged or not by manually pushing the needle forward to see if the water inside the tubing will come out. Note that there is a block of air before the water. So I get surprised when I see a drop or two of liquid before all of the air is pushed out... What do y'all suppose it is? At first I feared it was the virus itself, but that doesn't make sense because my injection needle should have deposited supposedly 250 nanoliters of the virus into the brain already, right?
Just this January, the CE instrument in our lab shows internal pressure system error (sometimes not ready with internal vacuum too). Initial solution is to tightened the plastic tubing #7 on the inlet prepuncher. Instrument was back on ready mode again. After few days, during an overnight run (which was not completed), the error showed up again. The following day, the tube was made sure it was tight again, the electrodes were cleaned, the prepunchers were clean, the module was checked for possible tubing problems or hindrances. And so the CE instrument was in ready mode again, and thankfully, I was able to ran a sequence. By this week, Monday, it reappeared again. Why is this so? Can anyone help me assess as to what could be the possible solution/s? Also, I noticed that whenever I will unscrew or open the replenishment bottles, it would produce air and sounds as if pressure was accumulated inside. Thank you in advance!
I have a netCDF file containig daily average temperature over 12 months ( 3D dimension: (lat, lon,time) ) it also contains some invalid data that is assigned to -9999.0 and NaN values. My task is to calculate statistics: monthly average, annual average and return the output as a netCDF file that have the same dimension of the input file and also i have to set back the invalid and NaN data into the output to preserve the initial format but i don't know how can i put the insert data into the corresponding latitude and longitude also when data are invalid or NaN how can i put it in the right position?
Here is a code in python but it generates an empty netCDF....
import netCDF4 as nc
import numpy as np
import numpy.ma as ma
import os
import datetime
warnings.filterwarnings("ignore")
file_name='temperature_moy.nc'
if os.path.isfile(file_name):
os.remove(file_name)
ds = nc.Dataset(file_name, mode="w")
xDim=ds.createDimension("lon", 1087)
yDim=ds.createDimension("lat", 462)
tDim=ds.createDimension("time", None)
var1 = ds.createVariable("MoyTemp", "f4", ("time","lon", "lat",))
times=ds.createVariable("time","i4",("time",))
_Y = ds.createVariable("lat","f4",("lat",))
_X = ds.createVariable("lon","f4",("lon",))
#add netcdf attributes
var1.units = "Celcius"
var1.long_name = "Surface air temperature"
_X.units = "meter"
_X.long_name = "longitude"
_Y.units = "meter"
_Y.long_name = "latitude"
times.units = "seconds since 2018-09-01 00:00:00.0"
times.long_name="time"
d = nc.Dataset('T.nc')
data1_var = d.variables["T2M"]
y=d.variables["lat"]
x=d.variables["lon"]
lat=y[:]
_lat=[i for i in lat]
lon=x[:]
_lon=[j for j in lon]
_X[:] = np.array(_lon)
_Y[:] = np.array(_lat)
#global attributes
ds.description = "netCDF mean temprature"
all_data = data1_var[:]
print(all_data.shape)
data_step1 = data1_var[1,:,:]
list1=[]
list2=[]
result=0
i=0
for x in range(1087):
for y in range(462) :
for t in range(12):
if str(data1_var[t,y,x])!='-9999.0' and str(data1_var[t,y,x])!='nan':
result+=float(str(data1_var[t,y,x]))
list1+=[result/int(data1_var.shape[0])]
result=0
list2+=[list1]
list1=[]
var1[0,:,:] = np.array(list2)
I have an O shaped water bath with a square cross section that I am circulating with an immersion circulator. How do I measure the flow rate at a given point in the bath? Can I use an anemometer even though that’s used for air?
Hello all,
I need to calculate the viscosity of some gases at High Temperature. I realize that I could use the Sutherland Law to evaluate such. However, from the Sutherland law/formula, there are two empirical coefficients (B and c). I got these two coefficients for AIR, but need your help for the coefficients of the following gases : Nitrogen (N2), Oxygen (O2), Carbon dioxide (CO2) and water vapours (H2O).
Thank you
We are using a GC with ISQ 7000 Mass Spectrometer. Today we did an air and water check and it was higher than usual, so we just tightened the ferrules. In the last two days, however, the N2 and O2 have increased and went up to 100% and 70% respectively. We checked for leaks, and there was no sign of any leakage. Any solutions?
Hello,
I have been trying to model evaporation at temperatures far well below 100C in Fluent. This is primarily driven by the vapor content of air at the water-air interface.
A saturation temperature UDF is attached below.
The setup this is used with has 2 phases, one a species mixture of air and water vapor and the other is water.
After some help from the forum, I have got it up and running and it seems to be performing fairly well in transient simulations. However, when I try to use this code to calculate the saturation temperature for any steady-state simulation, I get a floating-point error. This is sometimes instant and sometimes after a few iterations. An example error message is:
Error at Node 0: floating point exception
Error at Node 1: floating point exception
Error at Node 2: floating point exception
Error at Node 3: floating point exception
Stabilizing pressure correction to enhance linear solver robustness.
Stabilizing pressure correction using GMRES to enhance linear solver robustness.
Divergence detected in AMG solver: pressure correction Stabilizing temperature to enhance linear solver robustness.
Divergence detected in AMG solver: pressure correction
Divergence detected in AMG solver: pressure correction
Divergence detected in AMG solver: pressure correction
Error at host: floating point exception
I can't understand why I am running into this issue. Is there anything I could try to remedy the problem? I have tested on many geometries, with a variety of problems. Is this UDF unsuitable for steady simulations? and if that's the case then what alternatives do I have? I really need this functionality.
I thought it may be because the system varies a lot so I set up a closed system with a little water in with the walls set to a temperature of 300k and initialized it at 300k. My logic was that the only thing left to solve was the vapor fraction. I got a simulation to run 10000 iterations. However, the vapor fraction was 1.0 everywhere in the gas phase leading to relative humidities many times larger than 100%. This makes me worry there is something wrong with the UDF itself. I know that this kind of study must be possible somehow as I have read papers of people doing similar things, yet these don't go into enough detail for me to successfully imitate.
Any help is appreciated.
Cheers
#include "udf.h"
#define MOLAR_MASS_WATER 18.01534 //g/mol
#define MOLAR_MASS_AIR 28.97 // g/mol
#define RHO_WV 0.5542 // kg/m3
#define RHO_AIR 1.225 // kg/m3
DEFINE_PROPERTY(saturation_temp, c, t)
{
// t: mixture thread
// c: cell variable
// Cell volume
real vol = C_VOLUME(c, t);
Thread *pt = THREAD_SUB_THREAD(t, 0); // Primary phase thread
Thread *st = THREAD_SUB_THREAD(t, 1); // Secondary phase thread
// Get the volume fraction of both phases
real vf_s = C_VOF(c, st);
real vf_p = 1 - vf_s;
// Get the pressure of the mixture
real p_mix = C_P(c, t);
// Get the operating pressure
real p_op = RP_Get_Real("operating-pressure");
// Primary phase density
real rho_p = C_R(c, pt);
// Get mass fractions in primary phase
real mf[2]; // Array to store mass fractions
Material *m = THREAD_MATERIAL(pt);
Material *sp = NULL;
int i; // Species index - 0 for water vapor and 1 for air
mixture_species_loop(m, sp, i)
{
mf[i] = C_YI(c, pt, i);
}
real p_w; // h20 pressure for cell
// If secondary phase only
if (vf_s == 1)
{
p_w = p_mix + p_op; //****** I'm not sure if this is right *******
}
// If primary phase or mixture of phases
else
{
// Find the partial pressure of water vapour
// partial pressure = cell pressure * water mole fraction
// mass of primary phase in cell
real m_prim = rho_p * vol * vf_p;
// mass of water vapour and air in cell
real m_wv = mf[0] * m_prim;
real m_air = m_prim - m_wv;
// No of moles in water vapour and air
real N_wv = m_wv / MOLAR_MASS_WATER;
real N_air = m_air / MOLAR_MASS_AIR;
real N_total = N_wv + N_air;
// water vapour partial pressure
p_w = (C_P(c, t)+ p_op)* (N_wv / N_total);
}
// Calculate saturation temperature
real t_sat;
t_sat = (1730.63 / (10.196 - log10(p_w))) + 39.724;
return t_sat;
}
According to literature, the solubility of CO2 in water is approximately 1500 ppm. Maybe, this means that no matter how much flow rate of CO2 into the open chamber filled with water, the concentration of CO2 in water does not exceed 1500 ppm. Then, if I flow CO2 gas at 1 cc/min mix with Air flow at 1 cc/min into the open chamber filled with water, meaning that the flow ratio of CO2 : Air is 1 : 1, what will the concentration of CO2 in water? (1/2)x1500 ppm? Is this right?
Dear colleagues,
I am developing an HVAC MIMO model, through writing the state equations I am facing the attached state equation where in the third term, two states are multiplied in one term which creates a non-linearity in the system. The equation (part of eleven state equations) is attached
a,b,c and d are constants while (Tcc) is the cooling coil temperature, (Trfrgnt) is the temperature of the refrigerant (qsa) is the mass flow rate of the blown air, (Tra) is the temperature of the recirculated air and (To) is the ambient temperature
Now I face a problem of how to establish the A matrix (11 x 11), what is the best way of linearization of this particular equation? Do I need to linearize only the nonlinear term in the equation? Once linearized, does the linearized process effect the other state equations?
Kindly support and advise
Due to destructive development approach, finally this generation reached to self-created suicidal gas chambers commonly identified as cities with severe air pollutants. This can be observed across the world specially in fastest growing big economies of the world like India and China. There are many dimensions and factors need to be investigated to find out the root-causes.
Please suggest with your solutions based expertised opinions for:
What are the
- Major air pollutants?
- It's Cause/Effects?
- Affordable solutions?
Photo courtesy: https://images.app.goo.gl/NYfitYmQfC8uLnhJ7
Water is heated to 60 C and is atomized with compressed air into fine mist through a spray nozzle onto granulation bed. There is a drop in temperature observed in the water temperature upon reaching the bed. How to quantify the heat loss from the mist into surroundings through convection? The compressed air is atmospheric air.
As a hot area of research, do you recommend water sector or air?
To me, both of them are very essential to study and they plays the important role to protect the living environments. We can not live well if the toxic pollutants in air and water) spread over permitted limit.
Best regards.
Good evening everybody;
I am doing a research to produce a nanofiber membrane for HEPA (H14) filter production via electrospinning.
I have some questions:
1. I am spinning on a nonwoven substrate, should I calculate its area density (gsm) in the total gsm of the spun mat?
2. how could I judge on electrospun nanofiber based on the air permeability test results? i.e. I will check it according to standards (e.g. EN ISO 9237), the values will decrease by increasing gsm, when can I stop (range in mm/s)? before doing filtration efficiency test.
3. with your experience; should I keep some beads in the nanofiber web? or the spun mat should be beads-free? in literature both points of view are found.
Best Regards,
Dear All,
I have 2 full 2port s-parameters in 30mm waveguide section.
1. 30mm with air
2. 25mm with air and 5mm with material
And I want to extract the s-parameter of 5mm material from the above data.
I think that "de-embedding S-parameter" is solution.
But I don't know how to solve it.
Please give me a hint or calculate the solution.
Thank you very much!
Dear all,
I'm confused with the mass flow air's role in Indirect Rotary Dryer.
As far as I know, the air is there to carry evaporated moisture whereas the steam-tube is the one who will dried the product through heat transfer. Is that correct?
If that's the case, since the mass flow air's temperature will rise automatically through convection from the steam tube (which I consider as heat loss to air) then we don't have to calculate additional energy to raise the mass flow air from initial air temperature to the exit temperature do we ?
I only consider:
1. heat to raise products(dry+wet) from initial temperature to the desired temperature as sensible heat
2. latent heat for evaporating the water.
3. Heat loss due to radiation and convection to the surrounding (including heat loss to the said airflow)
In total, those are the heat requirement that must be supplied by the steam through heat transfer (conduction+convection) aren't they?
Really appreciate your kind reply and response.
Regards
I am working on air cooling in a room, and the AC unit can recirculate indoor air or air from outside, which depends on the user's settings.
CFD Tool- Ansys Fluent
Thank you
Common sense suggests that quarantine centers or ICU's where COVID patients are being treated have a high probability of transmission of virus especially to those providing assistance (doctors and nurses). My question here is there a measure to qualitatively or quantitively describe the air ( primary source of the virus spread) quality like PPM. If so how is the air quality in COVID affected areas different from COVID ICU's and how does it compare to COVID free areas. Can anyone please provide information or relevant literature on this topic.
Thanks in advance.
Hi,
I would like to ask, if my pressure outlet consists of lots of holes on a cylindrical wall, how should I extend the domain to prevent reverse flow?
Attached are the geometry of my outlet and my current fluid domain.
The fluid domain shown is a combination of volume extracted in SpaceClaim and a hollowed out cylinder as surrounding air. I had set the flat surface at the end and the curved surface as my pressure outlet.
However, when I ran the simulation, there is reverse flow from both the surface(almost 60%). From the pathlines, the air flows as such it is pulled by the gravity.
So, is it advisable to extend the domain like I did, or should I extend only the holes? It is gonna look like a lot of pillars emerging from the pipe.
Thanks in advance.
For the analysis of the aircraft compressor, I require the design data of the aircraft such as blade angles, air foil and stage parameters but I am unable to find any of it. Can someone guide me in this regard?
Are there any standard analytical methods for CS2 detection at such high concentrations?
CFD Computational Fluid Dynamics play a very important role for designing of air/vapour borne equipment like Spray dryers , air heaters, Vapour seperators etc
I am working on atmospheric modeling and I seem to have a problem obtaining meteorological data for the area under study, Athi River in Machakos County and Industrial Area in Nairobi, both areas in Kenya. Any assistance would be appreciated
Hello,
I am running a simulation with buoyancy on a very large scale (4000m high domain). I originally modeled air with Boussinesq approximation but I don't want the constant density. Therefore, I would like to model air as an ideal gas. Unfortunately, whenever I try this the air doesn't work properly and just falls. I tried to set up a pressure outlet at the top of the domain with the gauge pressure set to the drop in pressure at that altitude. This did not work. I even tried setting the drop in pressure to be twice as extreme with no luck. I set the operating pressure and reference density to what I expect the mean values to be (based on the height of the domain). I am using PRESTO! to solve pressure.
Nothing I have tried seems to work. The exact same setup worked perfectly with the Boussinesq approximation. Any help would be appreciated.
Calling SEM experts and those with SEM in bacteriology. We ran an air dried layer of LB cultured bacteria over the SEM stub. This is like some canalicules being witnessed. can this be bacteria. ON LB agar, we see swarming effect of this bacteria. Please help?
The system started taking up air once the water was over. There was no column attached. I'm now trying to run it in methanol to get rid of the air but I think its a lot. The UV is also over 200 mAU and so far I don't see anything flow out the waste tubing. What else can I do? Purging the system with Methanol hasn't worked so far as there is quite a bit of air inside. Any help would be much appreciated.
How to can calculate the thermal expansion of air. If there are an equation to calculate the thermal expansion of air, please provide me.
many thanks
For my CFD simulation in ANSYS.. I need a basic understandable geometry of a membrane.... Where the process is for inorganic membrane separation of Carbon Dioxide from heated air or natural air
I am trying to access annual consumption of household energy or annual household or indoor air pollution data - country-wise. for the year 2020.
Does anyone know where I can find the latest data for the year 2020?
When I run solution blank (2% HNO3), everything looks good. When it comes to air blank, Mn intensity is really high. I have tried to clean spray chamber but the problem still remains.
Do you have any suggestion?
Many thanks,
