Science topic

Metrology - Science topic

Science of measurement and its application.
Questions related to Metrology
  • asked a question related to Metrology
Question
28 answers
Relevant answer
Answer
Dear all,
thanks for your kind replies and comments !
As with other discussions that refer to experimental results, it is clear in the present one that responses generally do not refer to cited experimental results and procedures, but preferably rely on mainstream conform theoretical arguments.
Indeed, Stam Nicolis, citing "experimental" results from LIGO labs, concludes that both gravitational and electromagnetic waves travel at the speed of light. However, the validity of the LIGO results is still disputed in view of certain fundamental flaws in the experimental setup (see reference below), but is simply taken for granted without further discussion by the public in view of the general acceptance of the spectacular discoveries, including Nobel Prizes.
I would indeed be very grateful for any comments on the Keith experiment quoted above, especially since I believe that Julius Riese and László Attila Horváth are right when they mention that the gravitational speed could be faster than the speed of light.
  • asked a question related to Metrology
Question
7 answers
I need to measure the tip point of the drill bit using a non-contact pyrometer device. However, the thickness of the undrilled part and cutting fluid affect the measuring device for getting the exact temperature of the drill bit. So, is there any method for measuring the internal temperature of a solid body?
Thank you!
Relevant answer
Answer
You can measure Voltage and current by meters or a microcontroller IC and use ohm law.
For ANN implementation, MATLAB software can help you.
  • asked a question related to Metrology
Question
3 answers
I submitted my research paper in Measurement journal. Before build pdf stage, your journal asked money from me. I never paid a money. And proceed by clicking subscription. But I am not subscribed measurement journal. After that i approved my journal and submitted. If my research paper accepted, I need to pay how much amount?. Is any possibility to publish without money in measurement journal.
Relevant answer
Answer
I presume you mean this journal https://www.journals.elsevier.com/measurementThis is a so-called hybrid journal; this means that you can choose to publish using:
-Subscription option, meaning free for you as author and only accessible for readers with subscription (or license by their employer)
-Or open access option, which is free of costs for readers but then you need to pay APC
This open access option is not mandatory so you can choose the first option free of costs. As you can see here https://journalinsights.elsevier.com/journals/0263-2241/publication_options most authors do not choose the open access option.
Best regards.
  • asked a question related to Metrology
Question
5 answers
I am looking for a metrology tomograph for my lab. Ultimately, elements made of SLM-printed materials (steel and titanium alloys) will be X-rayed there. I mean a high-quality tomograph that would allow you to get high resolution images. Can someone recommend the manufacturer and model to me? Let me remind you - it is supposed to be a high-quality device for scientific purposes. Has anyone experience working with such equipment? I will be very grateful for any help.
Relevant answer
Answer
Dear Adam,
I hope I am not too late in this discussion. Am I correct in understanding that you are interested in purchasing an X-ray CT instrument? Or, are you looking to partner with someone who already has an instrument?
The reason I ask is because the quality of an X-ray CT measurement is dependent not only on the characteristics of the instrument components, but also on the effectiveness of any error corrections that are implemented during the measurement. The latter is particularly relevant when you are measuring metal parts, which are more prone to detrimental imaging artifacts due to beam hardening (projections are acquired with polychromatic X-rays, but reconstruction algorithm assumes monochromatic beam), X-ray scatter, and photon starvation (insufficient penetration of X-rays due to high absorption of metals). Some manufacturers provide built-in correction algorithms with their X-ray CT instruments for some of these effects, but I do not know how effective the corrections are.
In terms of the inherent instrument components that you want to look for, some important characteristics to consider are (not exhaustive, you can find more details in the references that Richard Leach provided among other literature out there):
1) The size of the X-ray tube source focal spot as a function of the tube power (see next point on tube voltage)
The focal spot size is one component of total image unsharpness, the other component being the response of the X-ray detector. The contribution of the focal spot size to total image unsharpness increases with the imaging magnification, and at some magnification position dominates the unsharpness to the point that detector unsharpness is negligible. The focal spot size, however, is not fixed and typically increases with the tube power, usually once the power exceeds ~9W. This dilation of the focal spot is done intentionally to prevent melting of the source target due to the increasing energy concentration at the focal spot, where it is known that 99% of the incident electron energy is converted to heat at the target. So, depending on the size and material of the object(s) you're trying to measure, you need to consider the specified focal spot size as a function of the tube power.
2) Tube voltage
The maximum achievable penetration length is largely dictated by the highest photon energies that your source can produce. So, when choosing an instrument, it is important to consider the maximum voltage of the tube source. However, take note that, with increasing voltage (which results in increased power), the focal spot size is increased.
3) Instrument geometrical stability
Most, if not all, instrument manufacturers implement sufficiently good procedures for ensuring geometrical alignment of their components--here, alignment is defined as consistency in the actual positions and orientations of source, stage axis of rotation, and detector with those assumed in the tomographic reconstruction algorithm. However, there could be residual effects due to error motions of the rotation stage and temperature variations within the X-ray CT cabinet. Particularly for high magnification measurements, these two sources could contribute to significant errors in the reconstruction.
As for artifact corrections, this is something that you would need to discuss with each instrument manufacturer. I would even suggest going as far as providing manufacturers with a sample that they would measure with their X-ray CT instruments and provide you with a reconstructed dataset. Then you can compare the quality of the reconstructions prior to making a decision on an instrument. Not all manufacturers will agree to this and your ability to visualize the reconstructions will also depend on the formatting of the reconstructed files. If the file is binary, you can easily open it using MATLAB or Python and you can perform a visual analysis of the image contrast and the presence/absence of imaging artifacts. If the file is a proprietary format, then you would need to agree with the manufacturer on how you can have (at least temporary) access to a software package that allows you to view it. Alternatively, you can touch base with someone you know who has VGStudio, Avizo, Dragonfly, or some other commercial volumetric analysis software package and ask them for help in this regard.
Alternatively, you can team up with one of many researchers out there who have implemented artifact correction approaches and see if you can implement them yourself. I generally recommend this approach as you will have full control and also full transparency of your data processing. I might be cynical, but when we are talking about measurements, I try not to rely on any 'black-box' approaches such as the ones often built into a measuring instrument.
Of course, a post on social media would not be complete without a bit of self-promotion, so I invite you to take a look at a very recent topical review on X-ray CT measurement traceability:
Don't hesitate to reach out if you want to go into more details about X-ray CT.
  • asked a question related to Metrology
Question
4 answers
I like to do linear laser measurements with environmental compensation and without environmental compensation. The parameters affecting linear laser reading are Pressure, Temperature, Humidity. For experimental purposes, I need to vary the Pressure, Temperature, and Humidity value. How I can select the Pressure, Temperature, and Humidity value? (randomly or any procedure available). Hint: The standard Pressure = 1013.25mbar, Temp=20C, Humidity=50%
And How much reading is required?
Relevant answer
Answer
As continue answer of Okasatria Novyanto I'd like to say that you need to use the system of 4 equations (as a minimum lot of equations) that relate 4 measured values ​​of the refractive index to 4 unknown parameters: the air temperature, the air pressure, humidity, and CO2 concentration.
  • asked a question related to Metrology
Question
7 answers
How to measure an optics thermal drift error in a laser measurement system(Renishaw XL80)?
Please tell me about optics thermal drift and what is the source for optics thermal drift. And How to find the value of optics thermal drift. And how to reduce it?
  • asked a question related to Metrology
Question
8 answers
The reasoning behind this question is to align the ratios of the proton potential in energy per charge to the speed of light in distance per time. As these two dimensions appear to be related, having identical numerical values would simplify the maths when making calculations in physics.
approximately;
(938,272,310 Joules per Coulomb)/(299,792,458 meters per second)
Basically setting the units so 1 J/C = 1 m/s
For our friends in the U.S. this would be like bringing back the foot ;)
In my brief paper below I show why potential and speed are one and the same thing.
Steven
Relevant answer
Answer
Steven Sesselmann , I don't understand your distinction between the absolute speed of light and the local speed of light. For example when LIGO detected a neutron star merger at a distance of 130 million light years it found that the gravitational wave and the light and gamma radiation all arrived at the same time.
Would you consider this to be the result of the local speed of light or the absolute speed of light?
Richard
  • asked a question related to Metrology
Question
12 answers
Anyone holds information regarding the typical hourly distribution of rain events in Australian cities (i.e. rain intensities, hour by hour) is welcome to contact me for a shared research/publication.
Currently, the (insufficient) data that is available for me is daily rain and IDF (intensity–duration–frequency) curves.
Please no comments which refers me to the BOM website :) thanks.
Relevant answer
Answer
look for NASA GPM
  • asked a question related to Metrology
Question
2 answers
Like for simulating oral cavity
Relevant answer
Answer
Temperature and humidity controller.
  • asked a question related to Metrology
Question
4 answers
Hello everybody,
Is there, by any chance, a statistical method that might help me determine whether two thermometers' data average differ significantly from one another? Since our laboratory does not have the right equipment at the moment to compare our data with we thought that maybe performing such an analysis would be of use, however, I'm lost.
I tried performing an ANOVA analysis, but that doesn't seem to solve my question since it'll only tell if the variances of each thermometer's registered data differ significantly, but what we're trying to verify is whether their averages are significantly differing, not their variances.
I've tried to solve this problem on my own, but don't seem to find a solution to it. Could anybody suggest any statistical analysis that might help here?
We usually register 5 to 10 data for each thermometer and we analyze at least 3 thermometers each time.
This is one of our data sets for contact thermometers A, B, C, and D (In °C)
A 36.6 36.8 36.7 36.6 36.7 36.7 36.7 36.7 36.9 36.7
B 37.2 37.1 37.0 37.0 37.0 37.0 37.0 37.0 37.0 36.9
C 37.2 37.2 37.2 37.2 37.2 37.3 37.3 37.3 37.2 37.3
D 37.3 37.2 37.2 37.2 37.3 37.2 37.3 37.3 37.3 37.3
We actually have a standard thermometer and for the thermometers, it works well with, we accept a maximum of +-1°C difference. However, we can't use any of them for a while.
Relevant answer
Answer
ANOVA
  • asked a question related to Metrology
Question
5 answers
Hello,I'd like to know how to submit papers in Metrology and Measurement Systems,thanks~
Relevant answer
Answer
Hello Ying Sha
You want to have a look to this page :
Cheers
Olivier.
  • asked a question related to Metrology
Question
18 answers
I have IMD grid data (0.25 by 0.25 resolution) in text format.
How to extract rainfall data of a river basin? any tutorials?
If it's not possible in ArcGIS any other software?
I am familiar with the Mann-Kendall Test and Sen's slop estimation etc, Can we use IMD gridded data for these analyses? any tutorials?
Can we convert IMD gridded data (0.25 by 0.25 resolution) to Taluk / District / Statewise for the analysis?
Relevant answer
Answer
Open the *.grd data using ENVI following these steps:
Step 1: Open the file and give parameters e.g. Samples = <no of columns>, Lines = <no. o frows>, Bands = 365, File type ENVI standard, Data type= Floating, Interleave = BSQ.
Step 2: Rotate the image by Angle = 270 and Transpose = Yes
Step 3: Change the Map Info.... Image X: 1, Image Y:1, Proj: Geographic Lat/Lon, Daturm: WGS84, E = 66.5, N = 37.5, X Pixel Size = 0.25 Deg, Y pixel size = 0.25 Deg
Step 4: Change geographic corner coordinates: Point 1: 1 (image X), 1 (Image Y), 37.5 (Lat), 66.5(Lon), Point 2: <no of column>, 1, 37.5, 100.5; Point 3: 1, <no. of rows>, 6.5, 66.5; Point 4: <no. of columns>, <no. of rows>, 6.5, 100.5.
thats it.. enjoy !!
Step 5: copy the *.hdr file and rename it as template.hdr and make a batch file (e.g. rename.bat) with command copy template.hdr <name of the other files> so that all four steps are not to be repeated next time.
  • asked a question related to Metrology
Question
11 answers
Hi, there!
I'm looking for information/standard/method about metrology for transient processes. I mean how to compare two or more charts with transient responses. I have no idea if this topic exist at all. All I have met is metrology for static measurements only.
Thank everyone. Every little help will be of great importance!
Relevant answer
Answer
Metrology is the core of geomatics that has been moven dramatically nowadays into computer vision applications for the seek of measurements.
It is using new technologies of digital image-based measurements studies.
  • asked a question related to Metrology
Question
12 answers
I'm working on a project that relates flooding to adequate Drainage system.
The project is area based (NSUKKA, Enugu Nigeria). Nusuka could be seen to have the geological features as stated above
Relevant answer
Answer
Highland is an area of elevation as against low plains or lowland. They are not necessarily flood plains. Its surface (topsoil) or subsurface soil may have high infiltration tendency that is, low runoff coefficient which may reduce flood risk. It may as well consist impermeable (mountainous) surface with large runoff coefficient which will increase flood risk as well. Basically runoff coefficient factor is essential as it relates the amount of runoff to the amount of precipitation received. However, with topographical variation either with steep or gentle gradient the low plains will be susceptible to flooding if adequate storm water channels are not implemented.
Hence, conduct flood risk assessment as suggested by Bayan Hussien and then classify your study area. Source for contour map or generate a topo survey using GIS software.
  • asked a question related to Metrology
Question
9 answers
I have a dynamic force +-4000N with frequency 1.5 Hz and I want to use a load cell to measure this force. 
Some peoples told me that load cell S type can withstand such little frequency !
I'm not sure so if anyone know then please guide me. 
Relevant answer
Answer
Dear Ahmed,
A load cell is a type of transducer, specifically a force transducer. It converts a force such as tension, compression, pressure, or torque into an electrical signal that can be measured and standardized. As the force applied to the load cell increases, the electrical signal changes proportionally. The most common types of load cell used are hydraulic, pneumatic, and strain gauge. Every load cell is subject to "ringing" when subjected to abrupt load changes. This stems from the spring-like behavior of load cells. In order to measure the loads, they have to deform. As such, a load cell of finite stiffness must have spring-like behavior, exhibiting vibrations at its natural frequency. An oscillating data pattern can be the result of ringing. Ringing can be suppressed in a limited fashion by passive means. Alternatively, a control system can use an actuator to actively damp out the ringing of a load cell. This method offers better performance at a cost of significant increase in complexity.
***Dynamic load cell is ideal for measuring force transients or dynamic force pulsations in impact or vibration applications. This load cell contains a thin piezoelectric crystal that generates an analog voltage signal in response to an applied dynamic force.
Proposed frequency range which is quite common may be classified for the dynamic loads are given below.
Resonant Frequency (@ No Load): 75 kHz High Frequency Range: 25 kHz (approx. 1/3 of resonant frequency, no load) Low Frequency Range (-3 dB): 0.08 Hz
Ashish
  • asked a question related to Metrology
Question
20 answers
Can I add it myself, or should these manipulations be performed only by the RG administration or the administrator who manages this institution profile?
Relevant answer
Answer
Dr Yehya A. Salih Thank you for useful information about changing my profile i knew really some new for me, but question was about an Institution page.
  • asked a question related to Metrology
Question
6 answers
All organs are not equally damaged by same amount of radiation dosage. But, on which basis equivalency is measured? (i..e 1 gray in this organ equals 10 sievert) Is it arbitrarily qualitative or quantitative as well? Then what is the quantity? ( concentration of reactive oxygen species, DNA mutation frequency, Radiative cellular apoptosis..., percent Coagulation of biomolecules). But all humans are not equally affected by same amount of radiation energy applied on same organ. Then, does the equivalency chart vary from person-to-person, species-to-species, or year to year ?(i.e. refining of values with increasing precision) I f so, thaen how the equivalency are standardized?
Relevant answer
Answer
For derivation of dose limits, radiation weighting factors, tissue weighting factors etc, you may be interested in
  • asked a question related to Metrology
Question
1 answer
I'm The Technical Manager of Force, Torque & Pressure Laboratories of Metrology Division, Sri Lanka Standards Institution.
Relevant answer
Answer
This question needs to be more specific
  • asked a question related to Metrology
Question
4 answers
Dear Sirs,
1, 2, 3 laws of Newtons need closed system (net force is zero). How do we practically realize, create such closed system?
One example. Let us look at a body motion. One can say If the body velocity is constant, e.g. zero then no forces act to it. Is it true? I think no. According to the 1st Newton law the velocity constance is the CONSEQUENCE of F=0.
So are there precise ways to construct closed system? Or all physical theory is just a mean to generate a hypothesis which has more higher probability to be true then other random thought?
Relevant answer
Answer
Dear Sir,
To the point how to construct.
Let us take component wise
Forces = Air frictional force if your relative velocity is high like 1m/s, frictional force from ground and touching surfaces, EM forces, Temperature gradients, Electrical Gradients, Gravitational forces.
Maintain constant Temperature that is generally room temperature- If temperature gradients exist then, source of it should be eliminated or considered in the system.
Use Glass material polished with talcum powder.
If any EM material Exist that is taken care by glass itself.
If high velocity Evacuate the chamber i.e. create vacuum.
Cover other surfaces also with talcum powder.
X & Z components are taken care by these.
Y component gravity is left that comes vey expensive.
So to eliminate gravity either use Archemedies Principle or do it simulation if real is not compulsory.
  • asked a question related to Metrology
Question
3 answers
The coordinate measuring machine (CMM) is a mechanical system that moves a measuring probe to determine the coordinates of points on the surface of a work piece. The CMM comprises: the machine itself; the measuring probe; the control system, and the measuring software. CMM is a precious excellence control to manufacturing,
Relevant answer
Answer
In manufacturing industry, metrology is so important that if your measurement devices doesn't have their calibration, the things produced aren't trustable and coherent to other devices. For instance the engine pistons aren't produced in terms of the calibration, they can't move in and out problem-free inside the engine mount.
  • asked a question related to Metrology
Question
5 answers
Is there any tool/technique that can help me in measuring thickness of double epoxy coating. Both are epoxy but with two different types of fillers. The resin could be same for both of them. The thickness scale could be from 20um - 500 um.
Relevant answer
Answer
If you use two different types of fillers you should receive two peaks associated with the ultrasonic wave reflection from the boundary coating 1 / coating 2 and coating 2 / substrate.I measured the three-coating system but very well defined. In addition, I had a relatively large surface for testing so I could use PIG (paint inspector gauge).
  • asked a question related to Metrology
Question
6 answers
Hello all,
This is a slightly strange one.
I need to convince a community of practice (field biologists) that they need to validate their tools and methods before they use them to generate results that are used as the basis for important management decisions.
While QC and validation have penetrated to the benches in biochemistry and microbiology labs, they are completely foreign to field biologists, for reasons that I will not burden you with here.
What I need is a basic introduction to QC and validation that is not specific to the hard sciences (physics and chemistry), and that sets out the fundamental reasons why knowing that a tool and a method work properly are essential steps in doing good science and generating results that can be relied on.
I have googled all the combinations of validation, QC, fit for purpose, etc etc that I can think of, and everything I find is too specific to particular applications - I need something that sets out the basic need for validation in general. Peer reviewed or a standard textbook is preferred, but anything clearly written will be a help.
Thanks.
Peter
Relevant answer
Answer
There are no appropriate texts! ICH validation guidelines apply to pharmaceuticals and biopharmaceuticals. With small molecules it has been relatively easy to validate a method but stem cells will be very hard. Is a recovery of 50% for a fluorescent antigen technique appropriate?
The 'validation biologist' will have to demonstrate that the method is consistent and reliable. This will mean setting the appropriate and relevant acceptance criteria or specifications.
  • asked a question related to Metrology
Question
25 answers
The Bermuda Triangle is one of the amazing landmarks in the world And there are strange, interesting and horrible events in that area. Events such as the crash of planes, the sinking of ships, the collapse of the compass, and etc. Scientists express different ideas for these events Like hexagonal clouds, deep earthquakes, atmospheric disturbances, methane gas and etc. And each of these reasons justifies part of the events in that area . What really happens in this area ? Could this be the cause of the extraterrestrials? Is there another area like the Bermuda Triangle?
Relevant answer
Answer
It is time for someone to do a serious study of these events. Not just one investigator, but many of various disciplines and specialties.
People have already solved the disappearance of dinosaurs, why not these phenomena?
  • asked a question related to Metrology
Question
3 answers
All the research papers I found so far, are just showing measurement of the squeezing parameter or quantum Fisher Information (QFI). Of course authors mention that, due to large QFI or strong squeezing this setup can be used for metrological purposes beyond standard quantum limit (SQL). I could not find any papers, which actually perform estimation of the unknown phase and show that the precision is beyond SQL. I am curious from the point of view of estimation in the presence of decoherence (which is always present). Theoretical papers indicate that entangled states are basically useless if frequency is estimated (e.q. Ramsey spectroscopy).
Relevant answer
Answer
I am not actually expert in this field and I am not sure whether the following paper is of your help, I just referred this if I could learn something from you and others.
Entanglement-free Heisenberg-limited phase estimation
BL Higgins, DW Berry, SD Bartlett, HM Wiseman, GJ Pryde, Nature 450 (7168), 393
  • asked a question related to Metrology
Question
1 answer
hello,
i am using cygwin. i have imported the snaphu in cygwin and it is running. it is showing some parameter variation like number of nodes in network, pivots, tree size. i have assured the the status of program using task manager of windows explorer. i am not getting how long it will run. it has been taken 48hrs already.
my system configuration is HP Z620, 24GB RAM, Windows8.1
Relevant answer
Answer
Hi,
I know this is an old question, but I want to add something here that might be useful. The unwraping process depends on the size and the quality (coherence) of the input interferogram. For Sentinel-1 full scene, with a computer running Windows 10 (16GB ram, Core i7) it takes up to 72 hours.
Regards
  • asked a question related to Metrology
Question
4 answers
This, in particular, might help explain LIGO statements like „There are families of glitches that we frequently see but have not yet discovered the cause of.“ - See reference below, last paragraph on page 24.
When measuring distances, isn't it an obvious idea to question our yardstick stability? We are talking about 10-18 m transients at 4 km distance.
Relevant answer
Answer
Everyone is talking about mirror displacements of order 10-18 m such as if laser wave trains of kilometer length would stay completely unaffected by spacetime and other kind of "ripples".
  • asked a question related to Metrology
Question
17 answers
From where to get a weekly or monthly rainfall data of any area in India? 
please suggest...
Relevant answer
Answer
Apart from IMD data you may find Tropical Rainfall Measuring Mission (TRMM) rainfall data for last 17 years.
  • asked a question related to Metrology
Question
2 answers
I find your project really interesting. At the moment I am collaborating with a small company in the field of metrology, specifically in developing procedure to optimize the quality in laboratory.
We have developed a new approach to use metrology: it is a software platform able to organize the metrology in different application field, such as an analytical laboratory, etc. Specifically, it permits to organize the calibration of all laboratory instrumentations (e.g. scales, pipettes, thermometers, etc.) and the intermediate checks by the use of control charts, to elaborate data and estimate the uncertainty of measurement with the use of different approaches, to verify during the time the metrological characteristics of the test methods by means different tools that assure the quality. Moreover, the validation protocols of the methods for the measurements can be organized by the use of statistic tests to realize the same protocol, in accordance with the technical sectorial standard.
We are really interested to collaborate with you in this topic research area.
Relevant answer
Answer
Stephen,
Thanks for responding on the project's behalf. The LUMINAR project is ended, and we are in the final bidding stages for a follow-on project called LaVA - Large Volume Applications - here we take some of the fundamental research from LUMINAR (and some new ideas) to generate some Demonstrators for Metrology Systerms operating in factory environments. These will involve aerospace, automotive manufacture, with cooperation between several systems such as photogrammetry, videogrammetry, laser trackers, Frequency Scanning Interferometry, spectroscopic refractive index measurement. These will be a mixture of more mature technologies and some tat are really early concepts. At the moment I suspect we are at too early a stage of technology level to apply formal quality system approaches, but that will be a requirement of the eventual end users.
Regards,
Andrew Lewis 
  • asked a question related to Metrology
Question
1 answer
I'm using a HAKKE MARS II rheometer. Im currently linearly increasing the strain by setting a fixed value for shear (strain) rate. My problem is for rates lower than 1/s, the measured values are always off by a factor of about 100.
Do you have any suggestions to improve the measurement? Thanks.
Relevant answer
Answer
The problem is that your rheometer is shear stress controlled, so when you ask for a shear rate, or strain, the instrument has to use a feedback loop to give you what you want. This task can be very difficult, depending on the sample rheology, as your results demonstrate.
I suggest thinking about exactly what rheological data you want and then trying to find a way to obtain it using the rheometer's stress control directly, e.g. with creep tests or shear stress ramps. This way you will always get what you ask for.
Good luck!
  • asked a question related to Metrology
Question
12 answers
I have a water container surrounded by the electrical heater with insulation. There is a temperature sensor and and opening for the compressed air supply below at the container .We were interested to measure the humidity at different temperature .We have measured the humidity with FTIR instrument which is supposed to be accurate. The reading shows by FTIR agreed to our calculated humidity for the temperature range till 90 degree but afterwards it got deviated largely from our calculated measurements. Meanwhile to be sure we have again measured the humidity with silica gel by gravimetric method. The reading obtained by silica gel also shows the same trend as shown by FITR like the silica gel readings were in agreement with our calculated measurement till 90 degree but not in agreement with higher temperature.
Has any one idea what might be the reason. I believed that my equation for humidity does not seems to be valid for higher temperature.Would like to hear feedback or suggestion for equation that will be valid for all temperature range.
Relevant answer
  • asked a question related to Metrology
Question
13 answers
I'm working on a metrology solution to work at cryogenic temperatures (80 K - 100 K). Ordinary photodiodes often have epoxy encapsulating the die wire bonds. At cryo temperatures, this epoxy shrinks, cracks, and breaks the wire. So I'm looking for a manufacturer that does not do wire bond encapsulation.
A second requirement is that the photodiode not have a window cover (or, at least, that it is easily removable).
Other specs - Si photodiodes, 10x10 mm active area, ceramic housing, NIR-sensitive (some have NIR-suppressed response, do not want that).
Any anyone suggest a supplier?
Relevant answer
Answer
Dear Boris,
May be one of the solutions is to use Si photo diode chips and mount them your self such that the mount can withstand the required low temperature 80-100 K.
In an experiment to measure the transistor chip  we mounted the chip on a PCB cupper clad board with silver epoxy and bonded gold wires between the pcb bond pads and the bond pads on the chip to access the diode electrically. Then wires are soldered to the terminals of the diode at the PCB boards. 
You can get the photo diode chips following the link:http://www.vishay.com/photo-detectors/pin-photo
or any other vendor
Best wishes
  • asked a question related to Metrology
Question
3 answers
It does not matter whether the method is estimated empirically or not, all that matters is to be reliable enough and get us results without having to make further measurements beyond what authors used when they proved the validity of their work.
The location of interest for me is North America.
Relevant answer
Answer
hi dear,
you can use this model if your location lies between mentioned range.
Page, J. K. "Methods for the estimation of solar energy on vertical and inclined surfaces from sunshine records for latitudes 40S-40N." Proc. 5th Solar Energy Conversion. Dept. Physics, Univ. of Waterloo, Canada (1979): 37-99.
Regards,
  • asked a question related to Metrology
Question
17 answers
How can one measure particle charge using oscilloscope and op amp integrator circuit along with a capacitor and faraday cup. I am unable to figure out how to approach. I have the circuit ready but when I test the faraday cup by touching charged capacitor, the oscilloscope doesn't show any visible change in voltage. How can I use all these components to get a particle charge. My plan is to drop the particles in the faraday cup and get the output voltage change from oscilloscope. Then calculate the charge with the help of rated capacitor. Also, I don't have any electrometer.  
Relevant answer
Answer
Hi anjan,
If I am correct, you are building a Charge Integrator circuit. Which needs only a feedback capacitor (very low capacitance say 100fF, 10 pF). For that IVC102 OP AMP has 750fA bias current will suitable.
 Transimpedance amplifier amplifier circuit with Very high Feedback Resistor circuit also be useful for your application. For that therere is Operational Amplifiers having ultra low bias current like LMP7721 (3fA), LMC662(2fA) and INA116(3fA) Instrumentation Amplifier will work on such low current measurement.
I am also building one Transimpedance amplifier circuit with LMC662 OP AMP and10Gohm feedback resistor. If you have any suggestion or query tell me.
  • asked a question related to Metrology
Question
6 answers
Tell me please, can someone tell where to take data graphically for different years and months of (city) area (eg Europe)?
Example:
Relevant answer
Answer
Dear Vadym,
You could get many European weather data from the ECA&D database :
Regards
Olivier
  • asked a question related to Metrology
Question
3 answers
Does any laboratory arrange tests for intercomparison of extensiometers - or arrange cources with extensiometers?
I have googled and asked arround but not found many possibilities right now.
Kind regards,
Jan/Metrology/FORCE Technology, Denmark.
Relevant answer
Answer
Dear Belma - I will ask IFEP. I allready get reference materials from them. I think I will arrange these tests myself. - If I can find the time.
  • asked a question related to Metrology
Question
6 answers
Good morning:
My name is Katherine Muñoz and I am a student of industrial engineering at the University of Colombia Coopertativa. Enter this site that made me curious because it is excellent. I am currently in a research project for accreditation of a laboratory based in the metrological assurance. I have no prior knowledge of the subject but want to learn and I saw this place I can find many people who want me contribute a bit to be able to carry out my research as a bibliographical source.
Thank you from my heart who can help me and I will be attentive to your comments ... I read, learn the subject .... Thank you.
Relevant answer
Answer
I recomende You to read International Vocabulary of Metrology - VIM. I think it will help you find answers to many questions.
  • asked a question related to Metrology
Question
4 answers
HELP....
What mathematical model can be used in a metrological assurance in clinical laboratory?
Relevant answer
Answer
Dear Katherine! Are You mean the formulas for the calculation of error and uncertainty? Or methods, measuring techniques? Explain, please, more accurately, and then I can answer you.
  • asked a question related to Metrology
Question
6 answers
Metrology infrastructure in developing countries?
Relevant answer
Answer
 We have provided a variety of services to various countries associated with metrology capacity building including consultancy, equipment supply, advice, bilateral comparisons at the highest level in preparation for signature of the CIPM MRA. Due to the wide range of subjects we cover I would suggest initial contact would be with our international team: international_enquiries@npl.co.uk 
  • asked a question related to Metrology
Question
1 answer
The applications of the LSA for adjusting values are very wide. My interest is limited here to the field of quantitative measurements and for two peculiar fields of high-accuracy measurements, where it is used for computing adjusted values of the so-called “universal constants” (CODATA task) and of the atomic masses (often called atomic weights) (AME, AMDC task), for two purposes: to obtain an evaluation the consistency with each other of these (large) sets of values with a minimised associated uncertainty; to provide a set of recommended values. I report at the end some basic references about these two frames and their use of the LSA.
The LSA is used for minimising, according to a L2 norm, the standard deviation of a set, by computing new values (or deviations from the original values, called “adjustments”) of each member of the set of quantities, and the new uncertainty associated to each member of the set—generally lower, thanks to the minimisation.
However, the system cannot provide ‘absolute’ adjusted values when any of the values can be assumed to be ‘exact’. In fact, at least one of the original values must be kept constant, so, in actuality, all the adjustments are relative to this member, taken as ‘reference’ (please note, this does not generally mean ‘exact’). Should another member be chosen as the fixed one, all adjustments would be different, with a peculiar characteristics: the differences between two members of the set still remain the same, irrespective to the choice of the reference. Sometimes more than one member is kept fixed: I skip here this case for simplicity.
This ambiguity stands unless an additional assumption is made, concerning the ‘best’ reference, ‘best’ according to a chosen criterium. This limitation arises directly from the fact that, in measurement, the ‘true’ value cannot be known; consequently, no objective way exist to state which member carries the correct numerical value, implying that its value should not be adjusted. In the case of the use of fundamental constants for the definition of the measurement units, the additional assumption might consist of an independent way to estimate the minimisation of the discontinuity between the units, before and after the change in definition, which should strictly be avoided.
In my opinion, the LSA is a sound method to evaluate the consistency of the set of values with the lowest associated uncertainty level, by taking advantage of the statistical properties of a larger overall set. On the contrary, as to obtain and recommend ‘best’ values for standard tables of nuclides or of fundamental constants, the fact that the LSA evaluation is biased by the arbitrary choice of the reference member(s) should be carefully taken in consideration: in my opinion this bias makes the method inappropriate for that purpose, with respect to statistical means to obtain the ‘best value’ for each member of the set. In addition, with the LSA a relationship is construed between all members of the set, which could conflict with the fact that they originally are, at least in part, independent with each other.
Some basic and latest references:
CODATA: http://physics.nist.gov/cuu/Constants/index.html, http://www.bipm.org/extra/codata/. Last adjustment: P.J. Mohr, B.N. Taylor and D.B. Newell, CODATA Recommended Values of the Fundamental Physical Constants: 2010, Rev. Modern Phys. 84 (2012) 1–94. LSA application: Cohen E R, Crowe K M and DuMond J W M 1957 The Fundamental Constants of Physics (Tamworth, UK: G. & J. Chesters); C. Eisenhart Spec.Publ. 300 NBS paper 4.5 (1961); F. Pavese, Metrologia 51 (2014) L1–L4.
AME, AMDC: http://www-csnsm.in2p3.fr/amdc/. Adjustments using LSA: A.H. Wapstra, G. Audi and C. Thibault, Nucl. Phys. A 729 (2003) 129, M. Wang, G. Audi, A.H. Wapstra, F.G. Kondev, M. MacCormick, X. Xu and B. Pfeiffer, Chinese Phys C 36 (2012) 1603.
Relevant answer
Answer
sorry I do not have the expertise to answer this question.
Regards
  • asked a question related to Metrology
Question
12 answers
For measurement of surface or thickness with high accuracy upto 1 micron which is best metrology  device.
Relevant answer
Answer
For large and transparent parts, optical interferometry via wavelength tuning can measure surface and thickness parameters simultaneously with sub-micron precision.
  • asked a question related to Metrology
Question
7 answers
kinetic for capacitive sensitivity of capacitive accelerometer is:
S=(delta)C/(delta)g
or S=(C2-C1)/(g2-g1)
for example 10fF/g.
Now how can I turned it to resolution?
that means for example one 2g accelerometer with 10fF/g sensitivity what is its resolutions? or conversely?
Relevant answer
Answer
Hi,
I think, you can use definition equation for Effective Number of Bits (ENOB):
ENOB=(SINAD-1.76)/6,02,
where SINAD is Signal to Noise and Distortion Ratio, in dB.
More you can find in Wiki of course:
  • asked a question related to Metrology
Question
8 answers
In order to analyze the displacement, an equipment that control the amount of displacement has to be used in the setup. Example, xyz translational stage. But this one limited to milli metre varition. I want to analyze the displacement in micrometer range. What is another equipment that can be used? 
Relevant answer
Answer
if you are looking for measurements to determine the accuracy of micrometer scale displacement , I suggest LVDT linear probe or laser interferometer.
if you want permanent setup which can give micrometer scale displacement, piezo is preferred.
  • asked a question related to Metrology
Question
1 answer
I believe, there may be something essential and special about the Ramanujan's numbers, let me first label the numbers (in honor of the genius Ramanujan) as:
Ri = 1, 3, 5, 11, 181. and
ri = 3, 4, 5, 7, 15.
to be the only solutions of the Ramanujan-Nagell equation:
2r = R2 + 7
It may be possible to express some of the famous mathematical constants in terms of the Ramanujan's Numbers, consider for instant the square root of 2:
sqrt(2) = 1.414 213 567...
the frequently used (and accepted) approximation of root 2 is:
99/70 = 1.414 285 714 ...
which differs from the correct value by about 7.215x10-5.
Now, let's discover what the Ramanujan's numbers say, consider:
(R5)(1/r5) = (181)(1/15) = 1.414 203 409 ...,
Differs by only 1.007x10-5.
a very good approximation for root 2 than (99/70).
I believe, one can find more mathematical constants that can be expressed in terms of the Ramanujan's numbers if one selects the right combination of them. Are there any additional notes about the Ramanujan's numbers from the readers?
Relevant answer
Answer
Yes, look my cotribution to Riemann hypotesisi of Zeta funcntion! I believe that it has been published shotly.
  • asked a question related to Metrology
Question
5 answers
Is there a simple expression for the effective sky temperature in terms of only the ambient air temperature and the solar irradiance?
Relevant answer
Answer
There are several correlations that vary from simple formulations, where The sky temperature depends only on the dry air temperature, to more complex formulations, where the sky temperature depends also on the air water vapor tension and the sky cloud cover. This paper might be useful.
  • asked a question related to Metrology
Question
5 answers
I had taken the 3D roughness value of precision milled Ti6Al4V workpiece surface in Alicona microscope. The parameter I considered is Sa (Average height of selected area) in microns. In Alicona Infinite microscope I got the reading as 11.0355µm, 3.9683µm, 1.4111µm, 1.0857µm, 0.9991524µm, and 0.8205437µm at 2.5X, 5X, 10X, 20X, 50X and 100X magnifications. Which magnification is usually considered and why? Why so much variation in values? kindly help.
PS: Attached other 3D roughness parameter values and image of the sample
Relevant answer
Answer
The ISO 25178 family describes relevant parameters for your measurement strategy. The required spatial resolution (better speaking: the optical resolution of the objective) depends on the width of your minimal surface feature you want to resolve. Furthermore, from the feature height you might be able to estimate the slope of the surface features, which gives you the required NA of the objective. Read the the ISO 25178 for more details.
  • asked a question related to Metrology
Question
2 answers
What is the relation between true reading and the reading given by an instrument having some least count?
Relevant answer
Answer
Thanks
  • asked a question related to Metrology
Question
5 answers
Hello, 
I`m wondering that is there any measurement technique to detect the height and shape of free surface of water in 3 dimensions.
I only know just taking picture from the side.
Thank you.
Relevant answer
Answer
Photogrammetry is a well established technique for doing this. 
I just did a Google search with "wave height measurement  photogrammetry" and got a large number of hits. I downloaded 2:
1) CLOSE RANGE PHOTOGRAMMETRIC MAPPING OF SEA WAVES FOR BETTER
HARBOR DESIGN
Hatzopoulos and Demetrios, ASPRS annual conference 2012
2) Using stereo photogrammetry to measure coastal waves.
S. de Vries et al, Journal of Costal Research, SI 56, 1484 1488, 2009
3) Also note that if you are able to float any material on the surface of the water that will make it relatively easy to do a stero or multi photogrammetric measurement of the surface in 3D and in a time sequence if required.
  • asked a question related to Metrology
Question
4 answers
I need precision parts made of various materials (steel, ceramics, aluminium) with machining processes (polishing, milling, EDM) into various levels of surface finish.
For example, it could be a few steel blocks, each made with EDM, milling, polishing respectively. And the milled blocks are milled into a few roughness levels.
Are there samples like these that are readily available for purchase, like surface comparison blocks. And what are the prices for these samples?
Relevant answer
Answer
You should look at comparison specimens. You can get these from Rubert + Co. Come and see me to discuss.
  • asked a question related to Metrology
Question
11 answers
I want to use to TOC data to study how meteorological parameters affect the concentration of tropospheric ozone in Bihar. 
Relevant answer
Answer
You can use the NASA Giovanni website to view gridded total ozone column from OMI: see http://gdata2.sci.gsfc.nasa.gov/daac-bin/G3/gui.cgi?instance_id=omil2g
And you can subset and download the raw data using Mirador: see http://mirador.gsfc.nasa.gov
The page http://disc.sci.gsfc.nasa.gov/Aura/data-holdings/OMI/omto3_v003.shtml also has links to tools to read the data files. Good luck!
  • asked a question related to Metrology
Question
10 answers
I want the last 10 years of meteorological data of a remote place. There isn't any field observatory, so can you provide me any reliable links which can provide these data based on some model? Any suggestions? 
Relevant answer
Answer
You can also have a look at the data set from the Climate Research Unit of University of East Anglia. It is a global monthly .5*.5 grid of meterological observations from 1901-2013. However, you should note that the time series will just refer to the long term monthly averages if there are no stations in the vicinity (few hundred km, check metadata)  of the pixel you are interested in.
  • asked a question related to Metrology
Question
11 answers
What is a common measurement standard for mouse ES cell/embryo (life and medical sciences) research?
 
DeSimone and the National Research Council committee state the following in “Convergence: Facilitating Transdisciplinary Integration of Life Sciences, Physical Sciences, Engineering, and Beyond”:
“Many believe that life and medical sciences have not focused as extensively as physics and engineering on developing common measurement standards and common guidelines for collecting data from biological samples. In order to move beyond information encoded in individual genomes to translational application, further attention to this challenge of standardization and reproducibility is required. Strategies adapted from the physics and engineering communities can contribute, although the complexity and individual variability of living organisms make measurement challenges in life and medical sciences unique.”
So, is this a legitimate problem that concerns life scientists explicitly or are engineers and physicists simply asking for too much because they can't appreciate the difficulty of measuring what we all should want to know? 
Is a common measurement standard for ES cell research, etc., the best someone has already done or is it defined as the best we can achieve for some stated purpose?  What is that purpose and the best we can achieve?  Can there be one colligated, stated purpose and measurement standard for something like, "in vitro generation of hemangioblasts for rejuvenation and health"?
Would a "stem cell scientist", a "developmental biologist", a "cell biologist", a "materials engineer", a "network physicist", a "computer scientist", a "physiologist", a "tissue engineer", a "geneticist", a "reasonably informed citizen" and a "potential patient" ( i.e., all who investigate) agree this is what we want to know? Why bother?  That is, what can we know in that future that we can't know now with current standards? 
 
If we achieve this standard, would we even know what we're looking at?  For example, if we saw regular flashing behavior associated with a construct that's not supposed to flash, how can we use that information?  Who is responsible for assigning meaning if the behavior is novel to everyone investigating?
 
If we can't achieve that standard, whose problem would that be?  Why should it be the biologists' problem?  Isn't 21st century biology different in that it encompasses and synthesizes all disciplines?
 
Speculations are also welcome, so please...     :)
Relevant answer
Answer
The Levin lab web page discusses our main interest, which is morphogenesis, the generation of shape during development and regeneration.  And I agree - lacking a standardized way of describing shapes inhibits interdisciplinary collaboration; in fact, it inhibits intradisciplinary comparisons.  Planform  ( http://planform.daniel-lobo.com) is one of the lab's attempts to standardize the description of planarian shape so that experiments can be compared.  In that case, the model is for one person to establish the standard and everyone agrees to participate.  We hope it will work.  
Am I correct that it is descriptions of 3D shape that we are talking about standardizing? There are a lot of issues under discussion here: how to describe shape as well as how to get everyone, in all fields,  to describe shape in the same way.  The former is the more easily addressed, the latter is about human nature, which is way over my head.   Metrology, the study of measurement, is out there.  There are methods for describing shape, geometric morphometrics being the one I know best.  I'm sure the topologists could teach us about shape descriptions.  But I think it has to come from a recognized authority.  NIST and the international body of meteorologists might have some very useful information on deciding on a standard and making everyone stick to it.  Ultimately, though, I believe it will be up to the Natures, Sciences, Cells, and the equivalent players in other fields, to make the editorial decision that they will not accept non-standardized descriptions.  If we must do it to publish, we will do it.  Given that Nature will publish graphs showing the s.e.m. instead of the standard deviation, I think it is an uphill battle.    
  • asked a question related to Metrology
Question
6 answers
In the ‘International vocabulary of metrology-basic concepts and associated
terms’ (VIM) JCGM200:2008 and IUPAC technical report, a reference measurement procedure is described as a measurement procedure accepted as measurement results fit for their intended use in assessing measurement trueness of measured quantity values obtained from other ‘measurement procedures’ for quantities of the same kind, in calibration, or in characterizing reference materials.
Relevant answer
Answer
"Reference procedure" has 2 1/2 meanings:
1) In a legal context, "reference methods" are those that are defined as correct. They may be very tedious, so labs can use other methods, but if there is a dispute, the result of the reference method counts. This is rather frequent in food analysis (e.g. the Kjeldahl method is the reference method for protein, although most people use the Dumas method) and also in clinical chemisty: here, organisations like the IFCC have defined "reference methods" for some parameters (e.g. enzyme activity), against which other methods (e.g. ELISA) are calibrated.
2) If one calibrates one method against results of another method, then the one against which one calibrates is the "reference method", as it is suposed to be more accurate (it may also only be the more established/older one).
1/2) The term "reference method" is also used as a meaningless, but prestige-carrying term to state that the method one uses (and that is usually developed by oneself) is very good/much better than any other method. So it's an easy way of self-promotion.
  • asked a question related to Metrology
Question
11 answers
I have a thin-walled machined tube which I want to measure for it's thickness deviation in different positions but I don't know how. The specs: L=500mm , Ri=58mm , Ro=60mm
Relevant answer
Answer
As Mohammadali has stated U/S sensors can be a solution but at one specific location or point of interest only.
When you say thickness at different positions, there are two ways,
1) Use your U/S thickness probe and let the tube slide through its entire length under the probe. This will give you linear profile (length-wise) of the thickness.
Alternately,
2) Hold the probe at one position, roll the tube for one rotation, this will give you the thickness along the circumference of the tube at that position.
2A) Then repeat this step at several positions along the length of the tube to get a better picture.
Hope this idea works better for you!
  • asked a question related to Metrology
Question
29 answers
All measurements are uncertain, so in experimental science one should always specify the uncertainty, u, attached to the measured value, y. There are at least two mainstream ways to do it:
(1) y +- u(random) +- u(systematic) (sorry the post does not allow correct format for formulas); this way is often used in physics, leaving separate the random and systematic components.
(2) y +- u; in this way, in u, the two components are combined in quadrature, after "corrections" are performed on the result, uncorrected for systematic effects; this way is normal in metrology.
The size of u also depends on the chosen confidence level of a confidence interval (under Bayes approach the naming is different).
There are other ways when non-probabilistic methods are used to estimate the uncertainty.
In all instances, the result of a measurement is represented by (at least) a couple of parameters (y,u).
The question is: would it be possible to formalise a definition and notation which does not depend on the choice of the method (e.g. probabilistic or not) for the category 'uncertain number', and build an arithmetic out of that?
I was prompted by the existence of other categories of numbers, e.g., complex numbers.
Mathematicians should have the best tools to succeed (like, e.g., it happened for the mathematics of intervals)
I have placed some problems arising when using 'uncertain numbers', as opposed to 'mathematical' numbers, in some of my publications. I attach here one of them.
Relevant answer
Answer
"a non-probabilistic value would be certain, by nature and definition"
this statement is simply false
if i know that a real number is in the unit interval, but i don't know where, then i have a non-probabilistic uncertain number - it is common in this case to impose a uniform distribution to make it a probabilistic number and gain the strength of probability theory, but that is adding an unjustified assumption, and those baseless assumptions often render a problem unsolvable by overly constraining the possibilities - if in addition i have a second number that i know is in the unit interval, and i further know that the product of the two numbers is 0.5, then i have a dependency that is not handled by any probability theory because the numbers are not probabilistic in the first place; they are merely uncertain
we have already explained that probability is not the only viable mathematically formal model of uncertainty (it is only the most popular and the most effective where it applies), so, while papoulis' book is excellent for probability theory, it intentionally and explicitly does not address the other issues that have been raised (the table of contents makes it clear that he is treating only probability theory and not any of the other approaches that have been mentioned), for which probability theory either does not work at all, or leads to much more clumsy computation than other methods - di finetti's book is excellent in his discussion of the very notion of probability, and it hints at some of the alternative methods
on the other hand, of course, the original question was about measurement uncertainty, for which probability theory has an excellent track record and centuries of successes
if this discussion seems confusing or contentious to any of the readers, just remember that probability theory was only invented in the late 1600's, roughly the same time as calculus and certainly earlier than any of the other models - in addition, it has a much more checkered and contentious development history - the problem is that it captures some common intuitions about uncertainty, but not others - and even the basic theory remains confusing to many people to this day (check out the Monty Hall paradox for an excellent example)
i hope it is clear that i am not disparaging probability theory; i am only saying that it is not the only possibility with useful applications and methods for dealing with uncertainty
  • asked a question related to Metrology
Question
10 answers
I'm pulsing an UV laser in a hot air jet, and imaging the Rayleigh scattering. But some particles in the flow seem to induce Mie scattering, confusing our measurements. Without filtering the flow, is it possible to separate the 2 scatterings contributions, by any mean (images post-treatment, polarization, etc..) ?
Relevant answer
Answer
You can usually separate the two by the spectral signature - the Rayleigh scattering is broadened by the thermal and acoustic motion of the gas, whereas the Mie scattering comes from a particle that has very little thermal of acoustic motion associated with it.This can be done using sharp cut off molecular or atomic filters.