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# Calculating mean path lengths in a magnetic circuit. Can it be this simple?

#### Noodler

Joined Dec 29, 2015
5
I am studying electronic principles and currently electromagnetic induction.

I have been having some trouble establishing mean path lengths and cant seem to find any information in my course notes.

I have looked on this forum and found what I think is some good information, but it looks a bit simple.
I have applied this to my question with the result showing as 73mm, please see attachment for question and my working out.
I think the hole or partial penetration in the plate at the bottom of the loop may be relevant to later questions regarding flux density
and MMF, but I am not sure.
Does this look right? it seems too simple.

#### Attachments

• 128.8 KB Views: 81

#### Kermit2

Joined Feb 5, 2010
4,162
I don't think that simple formula works if all 4 sides are not the same thickness. One side of your square has a 1mm thick side.
I got a slightly larger answer by deducing the length of your vertical path to be 17.5 mm and the horizontal path to be 21 mm. Do you see where I got the 17.5 mm?

#### Noodler

Joined Dec 29, 2015
5
I don't think that simple formula works if all 4 sides are not the same thickness. One side of your square has a 1mm thick side.
I got a slightly larger answer by deducing the length of your vertical path to be 17.5 mm and the horizontal path to be 21 mm. Do you see where I got the 17.5 mm?
I think I may becoming a bit number blind, I am attempting to resolve issues surrounding flux density and MMF for the circuit also, but with very little success at all. It may well be time for a break.

I cant see where the 17.5mm is from on the vertical path.

I am assuming that other than the 1mm section on the bottom, the other three sides are all 6mm.
As such the long vertical path looks like it has an overall length of 20mm plus 1mm. Giving 21mm.
Whilst the short path would be 21 minus the 6 at the top and the 1 at the bottom. Giving 14mm.
Regarding the horizontal path, the long path appears to be 25mm, whilst the short is this figure minus 2 x 6mm. Giving 13.

#### Kermit2

Joined Feb 5, 2010
4,162
You have a vertical distance of 20mm plus the 1mm steel plate. The mean path will start at the mid point of the upper section. This point is 3mm inside the upper leg. The coresponding halfway point on the bottom leg is 1/2 mm inside. So we have 20 minus 3 and an additional 1/2 mm. This adds to 17.5 mm of vertical distance on each side.
And DAMN IT.
The calculator gave me 77 mm as an answer the first time and gives me 73 mm now.

19+19+17.5+17.5=73

I think I have data entry dyslexia

#### Noodler

Joined Dec 29, 2015
5
You have a vertical distance of 20mm plus the 1mm steel plate. The mean path will start at the mid point of the upper section. This point is 3mm inside the upper leg. The coresponding halfway point on the bottom leg is 1/2 mm inside. So we have 20 minus 3 and an additional 1/2 mm. This adds to 17.5 mm of vertical distance on each side.
And DAMN IT.
The calculator gave me 77 mm as an answer the first time and gives me 73 mm now.

19+19+17.5+17.5=73

I think I have data entry dyslexia
Many thanks Kermit.
I have worked it both ways now and got the same answer.
The main thing is that it appears that I am actually finding the mean path length.
I was a little concerned, as it looked too simple in the end.

Thanks again, I can now continue to work the remainder of the problem.
That said I may well be back with more queries regarding my understanding or lack of it.

#### Jony130

Joined Feb 17, 2009
5,351
But for this circuit you have two mean path lengths. One length for Fe-Si and the second one for carbon steel plate.

#### MrAl

Joined Jun 17, 2014
9,179
Hi,

The mean magnetic path is just a measurement of length of the magnetic path, no matter what it goes through. There are other properties that are considered separately when all the items are not of the same material, such as the normal air gap (not this particular air gap however). The other properties would definitely include the width of the air gap (if it was a simple air gap) and for this problem the length of the steel plate. Those lengths would also need to be considered, but the mean path is still just the total distance a magnetic field line takes if it was located at the very center of the three dimensional sides. This single line is at the very center so for a side that has a square cross section 6mm by 6mm and any length the line is 3mm in from all surfaces of that one side. If the cross section was 6mm by 8mm then the line would be 3mm in from one surface and 4mm in from the other surface. But usually these problems only use 2d drawings so we only see 6mm or 8mm and then we assume that the other dimension is also uniform, so we just divide by 2 and get either 3mm or 4mm respectively.

So the first thing to do is calculate the mean magnetic path, then later we would have to know the length of the steel plate and perhaps the length of the core that is not the steel plate, but only if the permeability for each material was different, which they usually are. So it does make sense to note that there could be more than one length involved, but this problem seems to be asking for that one mean length.

The mean length that has already been noted follows a line at the very center of each arm of the construct, and runs the length of an arm from the center of the butt at one end to the butt of the other end. This has already been drawn out nicely in the attached pdf.

For a circular core the mean path is the sum of the outside circumference and the inside circumference, then divided by 2. For a square or rectangular construct it would be the same i would think, although we could prove this algebraically.

In any case though, the mean path here is 73 because no matter how you calculate it, the result is the same.

I'll see if i can work up a proof if i have time. For example, if the width of one side is A and outside length L, and the width of one of the butts is B and the other C, then the mean length of the side A is:
Lm=L-B/2-C/2

and we would just need an expression for the whole thing and another expression for the other method and then equate the two. If they equate algebraically, then they are the same. For that one side though we would also know the inside length K is:
K=L-B-C

so the mean this second way would be:
Lm=(L+K)/2
so:
Lm=(L+L-B-C)/2=(2*L-B-C)/2
so:
Lm=L-B/2-C/2

so it does seem to prove that both methods are the same because every side would be calculated using the same procedure. We might have to look at angled sides too, but that's probably the same since the circular shape works the same.

Last edited:

#### Noodler

Joined Dec 29, 2015
5
But for this circuit you have two mean path lengths. One length for Fe-Si and the second one for carbon steel plate.
Thank you.
I believe that the two different material types are related to another part of the question regarding calculation of MMF.
That said I could well be misinterpreting the question.
It asks what the MMF is in each part of the path of the circuit to achieve B in the specimen plate of 0.5T.
I have magnetization curves for the materials concerned.
It looks as if I have to work out MMF for the specimen plate with known dimensions and B and H values from the relevant curve.
Taking this answer as one path.
I think the remaining three paths (legs on the electromagnet) should all be the same and could be calculated using their dimensions and B and H values from their relevant curve.
I think this makes sense?
I believe that I have an equation here to calculate MMF, but it looks a wee bit complicated to me at the moment.
Thanks again.

#### Noodler

Joined Dec 29, 2015
5
Hi,

The mean magnetic path is just a measurement of length of the magnetic path, no matter what it goes through. There are other properties that are considered separately when all the items are not of the same material, such as the normal air gap (not this particular air gap however). The other properties would definitely include the width of the air gap (if it was a simple air gap) and for this problem the length of the steel plate. Those lengths would also need to be considered, but the mean path is still just the total distance a magnetic field line takes if it was located at the very center of the three dimensional sides. This single line is at the very center so for a side that has a square cross section 6mm by 6mm and any length the line is 3mm in from all surfaces of that one side. If the cross section was 6mm by 8mm then the line would be 3mm in from one surface and 4mm in from the other surface. But usually these problems only use 2d drawings so we only see 6mm or 8mm and then we assume that the other dimension is also uniform, so we just divide by 2 and get either 3mm or 4mm respectively.

So the first thing to do is calculate the mean magnetic path, then later we would have to know the length of the steel plate and perhaps the length of the core that is not the steel plate, but only if the permeability for each material was different, which they usually are. So it does make sense to note that there could be more than one length involved, but this problem seems to be asking for that one mean length.

The mean length that has already been noted follows a line at the very center of each arm of the construct, and runs the length of an arm from the center of the butt at one end to the butt of the other end. This has already been drawn out nicely in the attached pdf.

For a circular core the mean path is the sum of the outside circumference and the inside circumference, then divided by 2. For a square or rectangular construct it would be the same i would think, although we could prove this algebraically.

In any case though, the mean path here is 73 because no matter how you calculate it, the result is the same.

I'll see if i can work up a proof if i have time. For example, if the width of one side is A and outside length L, and the width of one of the butts is B and the other C, then the mean length of the side A is:
Lm=L-B/2-C/2

and we would just need an expression for the whole thing and another expression for the other method and then equate the two. If they equate algebraically, then they are the same. For that one side though we would also know the inside length K is:
K=L-B-C

so the mean this second way would be:
Lm=(L+K)/2
so:
Lm=(L+L-B-C)/2=(2*L-B-C)/2
so:
Lm=L-B/2-C/2

so it does seem to prove that both methods are the same because every side would be calculated using the same procedure. We might have to look at angled sides too, but that's probably the same since the circular shape works the same.
Thank you, it looks like I have the mean path length calculated correctly.
Your confirmation and the explanation of this is much appreciated.

I believe that the two different material types are related to another part of the question regarding calculation of MMF.
It asks what the MMF is in each part of the path of the circuit to achieve a certain B in the specimen plate.
I have magnetization curves for the materials concerned.
It looks as if I have to work out MMF for the specimen plate using known dimensions and B and H values from the relevant curve.
Taking this answer as one path.
I looks like the remaining three paths (on the electromagnet) should all be the same and could be calculated using their dimensions and B and H values from their relevant curve.
I think this makes sense.
I believe that I have an equation here to calculate MMF, but it looks a wee bit complicated to me at the moment.
Thanks again.

#### mildred00

Joined Dec 8, 2015
1
Noodler,

Have you had any luck with calculating the MMF for each part of the circuit?


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# subversion-users mailing list archives

##### Site index · List index
Message view
Top
From Dan Ellis <danelli...@gmail.com>
Subject Re: Incorrect error message on svn copy? Advice?
Date Wed, 21 May 2014 14:48:40 GMT
On Wed, May 21, 2014 at 3:22 AM, Ryan Schmidt <
subversion-2014@ryandesign.com> wrote:

>
> On May 20, 2014, at 17:02, Dan Ellis wrote:
>
> > I'm attempting to copy a file from a working copy to the server, but
> using an incorrect case for one of the folders in the path.  The paths all
> exist and everything works fine using correct case.  In the example below,
> "FOO" exists on the server as "foo".
> >
> > (Case 1)
> > c:\Project_files\sandbox>svn copy bar.c
> http://svr/repo/some_project/FOO/bar.c -m "text commit"
>
>
> You're trying to create something in the non-existent directory FOO, which
> is an error. It never gets to the point of calling your hook script. (The
> message might be clearer if it said "Directory not found: …, path
> '/some_project/FOO/bar.c'".)
>
> > If I use --parents to create the path (in case it doesn't exist):
> >
> > (Case 3)
> > c:\Project_files\sandbox>svn copy --parents bar.c
> http://svr/repo/some_project/FOO/bar.c -m "test commit"
> > ** ERROR-CASE: Clash: '/some_project/FOO' '/some_project/foo'
>
> You've asked Subversion to create a directory FOO when a directory foo
> already exists, which would be fine, except your hook script prevents case
> collisions.
>

My question revolves around why the different behavior/messages when the
only difference is when --parents is included. One case bombs out with a
cryptic message (svn: E155011: File 'C:\Project_files\sandbox\bar.c' is out
of date) and the other triggers a pre-commit check.  Both would seem to
(--parents would create it).  Why didn't case 1 trigger the pre-commit
check?  Granted, the script in question may be out of scope of this list.

>
> > As I would expect, I cannot perform an "svn info" on the incorrect-cased
> path.  I was hoping I could do an "svn info" to test/determine what the
> case corrected path is, but will have to try an "svn copy --parents" first
> and if it fails due to a case clash, retry with the returned clash info.
>  Is there a better way to accomplish this?  I do understand this is more of
> a corner use case, especially since Subversion is (properly IMO) designed
> around case sensitivity.
>
> What exactly are you trying to accomplish? If the problem is that you
> don't know the names (or cases) of the directories in the repository, then
> you can use "svn ls" to find out.
>

Doing an "svn ls" is burden-some when you have a lengthy path that you want
to discover the case sensitive version of.  If you had A/b/C/d/E for a
path, you'd have to "svn ls" on the repo to find "A" vs "a" then do another
for "B" vs "b" etc.  I'd like to know of the easiest method to discover
A/b/C/d/E vs doing an svn copy --parents to have the server side report
back the case sensitive version of it.  Plus, from a previous email,
there's no stock way to do "svn list" and return only the directory listing
(you have to wade through all the files as well).

I guess the normal and usual use case is having a working copy checkout so
you can locally navigate the repo structure.  In our case, we are doing an
archive type of operation where we really do not want a local WC due to
size and just operation on the repo directly.  svn copy works great in this
case with the exception of users getting case confused.

I appreciate the feedback.

Thanks
Dan

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A planet of mass (m) is moving around a star of mass (M) and radius (R) in a circular orbit of radius (r). The star abruptly shrinks to half its radius without any loss of mass. What change will  there in the orbit of the planet?

Discussion:

A planet of mass (m) is moving around a star of mass (M) and radius (R) in a circular orbit of radius (r). The star abruptly shrinks to half its radius without any loss of mass.

As we know, the formula for centripetal force is $$F=\frac{mv^2}{r}$$

Since the radius of the star is decreasing without any change in mass will not have any effect on force exerted by star on planet which is the required centripetal force.


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FORTRAN

Java JAXB

# IgorPro¶

An import tool (binding) for IgorPro has been created (cansasXML.ipf). You can check out the IgorPro working directory from the SVN server (see instructions below).

To use the canSASxml.ipf procedure, you must have the XMLutils XOP IGOR plugin installed. See the Usage Notes section below.

Note

Note that this tool is not a true binding [1] in that the structure of the XML file is not replicated in IgorPro data structures. This tool reads the vectors of 1-D SAS data (Q, I, ...) into IgorPro waves (Qsas, Isas, ...). The tool also reads most of the metadata into an IgorPro textWave for use by other support in IgorPro.

 [1] For example, see data binding from http://en.wikipedia.org/wiki/Binding_%28computer_science%29

Note

Note that the code described here is not a complete user interface. (See further comments below.) It is expected that this code will be called by a graphical user interface routine and that routine will handle the work of copying the loaded SAS data in IgorPro from the root:Packages:CS_XMLreader data folder to the destination of choice (including any renaming of waves as desired).

file: http://www.cansas.org/trac/browser/1dwg/trunk/IgorPro/cansasXML.ipf Pete R. Jemian 2013-03-29 1.12 (requires latest XMLutils XOP – see below) Implement an IgorPro file reader to read the canSAS 1-D reduced SAS data in XML files that adhere to the cansas1d:1.1 standard.
requires: IgorPro: http://www.wavemetrics.com XMLutils XOP: http://www.igorexchange.com/project/XMLutils minimum requirement: IGOR.5.04.x-1.x-dev (circa 2008-Aug-22)

## Checkout of support code in Subversion¶

Subversion (http://subversion.tigris.org/) is a program for managing software versions. There are command line and GUI clients for a variety of operating systems. We won’t recommend any here but will show the command lines necessary.

### XMLutils XOP¶

The XMLutils XOP, written by Andrew Nelson (ANSTO), is hosted on the IgorExchange (http://www.igorexchange.com/).

One good location to place the checked out XMLutils directory is in the Wavemetrics directory, next to the Igor Pro Folder.

Here is the subversion checkout command:

svn co svn://svn.igorexchange.com/packages/XMLutils/ XMLutils

To retrieve an updated version of this support in the future, go into the XMLutils directory (created above) and type either of these commands:

svn update
svn up

This will check the repository and update local files as needed. If the installer program was updated, you’ll need to run the new installer program. It is not necessary to uninstall first.

The installer executables contained in the download will do all the installation for you. They will place the XOP in the folder /User Procedures/motofit/XMLutils, and create a shortcut/alias to the plugin in ./Igor Extensions. Packages from other facilities should place the XOP there as well.

### cansasXML.ipf¶

Check out the canSAS 1d SAS XML reader from the subversion repository:

svn checkout http://www.cansas.org/svn/1dwg/trunk cansas-1dwg

This will download lots of extra files. The file of interest is in the IgorPro directory and is called cansasXML.ipf

To retrieve an updated version of this support in the future, go into the cansas-1dwg directory (created above) and type the command:

svn update

This will check the repository and update files as needed.

## Installation¶

1. License and Install the IgorPro application

(should have already done this step by now)

2. Quit IgorPro if it is running

3. Download XMLutils XOP. Either checkout from subversion (see above) or, with a

web browser, visit http://svn.igorexchange.com/viewvc/packages/XMLutils/trunk/

4. Install XMLutils XOP by double-clicking the installer for your operating system.

5. Download cansasXML.ipf. Either checkout from subversion (see above) or, with

a web browser, copy cansasXML.ipf from the on-line subversion repository. (http://www.cansas.org/svn/1dwg/trunk/IgorPro/cansasXML.ipf)

6. Copy cansasXML.ipf file to ...WavemetricsIgor Pro FolderUser Procedures

(or file system equivalent)

7. Then, you should be able to restart IgorPro and progress from there.

## Usage Notes¶

To use the canSASxml.ipf procedure, you must have the XMLutils XOP IgorPro plugin installed. This may be downloaded from the IgorExchange Project site. There are installer executables contained in the download that will do all the installation for you. Each installer will place the XOP in the folder ...Wavemetrics:Igor Pro Folder:User Procedures:motofit:XMLutils, and create a shortcut/alias to the plugin in ...Wavemetrics:Igor Pro Folder:Igor Extensions.

## What it does¶

Given an XML file, CS_XmlReader(fileName) attempts to open the file and read its contents as if it conformed to the canSAS XML standard for reduced 1-D SAS data (cansas1d:1.1, also known as SASXML). If the file is found to be non-conforming, then CS_XmlReader(fileName) returns with an error code (show below), otherwise it returns 0, indicating no error. All data read by this code is left in the IgorPro data folder root:Packages:CS_XMLreader for pickup by the calling routine. (Two examples are provided to show how a routine might retrieve the data.)

After opening the XML file (with a file identifier fileID), control is passed to CS_1i_parseXml(fileID) which then walks through the XML elements. For each SASentry in the file, a new data folder is created with the name derived from the Title element (or best effort determination). Efforts are taken to avoid duplication of data folder names (using standard IgorPro routines). For SASentry elements that contain more than one SASdata element, a SASdata folder is created for each. The corresponding $$I(Q)$$ is placed in that subfolder. When only one SASdata is found, the $$I(Q)$$ data is placed in the main Title folder.

data columns
Each column of data in the SASdata/Idata/* table is placed into a single IgorPro wave. At present, the code does not check for non-standard data columns.(The capability is built into the code but is deactivated at present).
metadata

Additional metadata is collected into a single text wave (metadata) where the first column is an identifier (or key) and the second identifier is the value. Only those keys with non-empty values are retained in the metadata table.

Caution

The values are not checked for characters that may cause trouble when placed in a wave note. This will be the responsibility of the calling routine to clean these up if the need arises.

The code checks for most metadata elements and will check for repeated elements where the standard permits.

Here is an example of the metadata for the Case Study: Dry Chick Collagen.

metadata for the cs_collagen_full.xml case study

row i key: metadata[i][0] value: metadata[i][1]
0 xmlFile cs_collagen_full.xml
1 namespace cansas1d:1.1
2 Title dry chick collagen, d = 673 A, 6531 eV, X6B
3 Run Sep 19 1994 01:41:02 am
4 SASsample/ID dry chick collagen, d = 673 A, 6531 eV, X6B
5 SASinstrument/name X6B, NSLS, BNL
6 SASinstrument/SASsource/radiation X-ray synchrotron
7 SASinstrument/SASsource/wavelength 1.898
8 SASinstrument/SASsource/wavelength/@unit A
9 SASinstrument/SASdetector/@name X6B PSD
10 SASnote
Sep 19 1994     01:41:02 am     Elt: 00090 Seconds
ID: No spectrum identifier defined
Memory Size: 8192 Chls  Conversion Gain: 1024  Adc Offset: 0000 Chls

dry chick collagen, d = 673 A
6531 eV, X6B
XML foreign namespace elements
These are ignored at this time.
XML namespace and header
The routine does a best-efforts check to ensure that the given XML file conforms to the required XML file header. If you take a minimalist view (a.k.a. a shortcut), it is likely that your file may be refused by this and other readers. Pay particular attention to UPPER and lower case in the text cansas1d:1.1 as this is a key component used to index through the XML file.
XML stylesheet processing-instruction is not generated

The XMLutils XOP package does not provide a method to insert the prescribed XML stylesheet processing-instruction into the XML data file.

<?xml-stylesheet type=text/xsl href=example.xsl ?>

If this processing-instruction is desired, it must be added to each XML data file by other methods such as use of a text editor or application of an XSLT transformation.

## Important Functions¶

These are the important FUNCTIONS in the cansasXML.ipf code.

CS_XmlReader(fileName)
reads the named XML file and and loads SAS data
prj_grabMyXmlData()
demonstration function to show a usage example
prjTest_cansas1d()
demonstration function to show a usage example

## Example test case¶

Here is an example running the test routine prjTest_cansas1d().

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 *prjTest_cansas1d() XMLopenfile: File(path) to open doesn't exist, or file can't be opened elmo.xml either not found or cannot be opened for reading Completed in 0.00669666 seconds XMLopenfile: XML file was not parseable cansasXML.ipf: failed to parse XML Completed in 0.0133704 seconds root element is not SASroot with valid canSAS namespace Completed in 0.0134224 seconds bimodal-test1.xml identified as: cansas1d:1.1 XML file Title: SAS bimodal test1 Completed in 0.068654 seconds root element is not SASroot with valid canSAS namespace Completed in 0.0172572 seconds root element is not SASroot with valid canSAS namespace Completed in 0.0123102 seconds root element is not SASroot with valid canSAS namespace Completed in 0.00930118 seconds ISIS_SANS_Example.xml identified as: cansas1d:1.1 XML file Title: standard can 12mm SANS Completed in 0.0410387 seconds W1W2.xml identified as: cansas1d:1.1 XML file Title: standard can 12mm SANS Title: TK49 standard 12mm SANS Completed in 0.0669074 seconds ill_sasxml_example.xml identified as: cansas1d:1.1 XML file Title: ILL-D22 example: 7D1 2mm Completed in 0.0332752 seconds isis_sasxml_example.xml identified as: cansas1d:1.1 XML file Title: LOQ TK49 Standard 12mm C9 Completed in 0.0388868 seconds r586.xml identified as: cansas1d:1.1 XML file Title: ILL-D11 example1: 2A 5mM 0%D2O Completed in 0.0213737 seconds r597.xml identified as: cansas1d:1.1 XML file Title: ILL-D11 example2: 2A 5mM 0%D2O Completed in 0.0221894 seconds xg009036_001.xml identified as: cansas1d:1.1 XML file Title: det corrn 5m Completed in 0.0286721 seconds cs_collagen.xml identified as: cansas1d:1.1 XML file Title: dry chick collagen, d = 673 A, 6531 eV, X6B Completed in 0.0296247 seconds cs_collagen_full.xml identified as: cansas1d:1.1 XML file Title: dry chick collagen, d = 673 A, 6531 eV, X6B Completed in 0.0751836 seconds cs_af1410.xml identified as: cansas1d:1.1 XML file Title: AF1410-10 (AF1410 steel aged 10 h) Title: AF1410-8h (AF1410 steel aged 8 h) Title: AF1410-qu (AF1410 steel aged 0.25 h) Title: AF1410-cc (AF1410 steel aged 100 h) Title: AF1410-2h (AF1410 steel aged 2 h) Title: AF1410-50 (AF1410 steel aged 50 h) Title: AF1410-20 (AF1410 steel aged 20 h) Title: AF1410-5h (AF1410 steel aged 5 h) Title: AF1410-1h (AF1410 steel aged 1 h) Title: AF1410-hf (AF1410 steel aged 0.5 h) Completed in 0.338425 seconds XMLopenfile: File(path) to open doesn't exist, or file can't be opened cansas1d-template.xml either not found or cannot be opened for reading Completed in 0.00892823 seconds 1998spheres.xml identified as: cansas1d:1.1 XML file Title: 255 nm PS spheres Title: 460 nm PS spheres Completed in 2.87649 seconds XMLopenfile: File(path) to open doesn't exist, or file can't be opened does-not-exist-file.xml either not found or cannot be opened for reading Completed in 0.00404549 seconds cs_rr_polymers.xml identified as: cansas1d:1.1 XML file Title: Round Robin Polymer A Title: Round Robin Polymer B Title: Round Robin Polymer C Title: Round Robin Polymer D Completed in 0.0943477 seconds s81-polyurea.xml identified as: cansas1d:1.1 XML file Title: S7 Neat Polyurea Completed in 0.0361616 seconds

## IgorPro Graphical User Interface¶

At least two groups are working on graphical user interfaces that use the canSAS 1-D SAS XML format binding to IgorPro. The GUIs are intended to be used with their suites of SAS analysis tools (and hide the details of using this support code from the user).

Note

There is no support yet for writing the data back into the canSAS format. Several details need to be described, and these are being collected on the discussion page for the XML format

### Irena tool suite¶

Jan Ilavsky’s Irena tool suite for IgorPro has a GUI to load the data found in the XML file. Refer to http://usaxs.xor.aps.anl.gov/staff/ilavsky/irena.htm for more details.


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# Generalizing Quadratic Reciprocity Law with Dilates

Eisenstein's proof of the Quadratic Reciprocity (QR) (and its Jacobi symbol generalization) both rely on counting lattice points in two congruent triangles. If we take $t$-dilates of these triangles, does an extension of Gauss' Lemma still hold with some dependence on $t$? That is, can we assign a Legendre symbol $(p|q)$, or some simple extension thereof depending on $t$, to $(-1)^{M(t)}$, where $M(t)$ is the number of lattice points in the $t$-dilate of the same triangle used in the standard proof and derive from it a "$t$-dilated" version of QR?

-
what is a t-dilate? – quanta Mar 11 '11 at 17:20
Suppose $P$ is an $n$-polytope of the form $\text{conv}\{\mathbf{0}, a_1 \mathbf{e}_1, \dots, a_n \mathbf{e}_n \}$. Then a non-trivial $t$-dilate $t P$ is the convex hull $\text{conv}\{\mathbf{0}, a_1 t \mathbf{e}_1, \dots, a_n t \mathbf{e}_n \}$, where $t > 1$. The triangles above correspond to taking $n = 2$. – user02138 Mar 11 '11 at 17:33


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# Optimize Max-flood algorithms bounds

In distributed algorithms, The Max Flood algorithms finds the leader in a network of processes In O(diam) time and with |E|*diam (|E| is the number of edges in the graph) message complexity. With some optimization in the algorithm we can reduce these message complexity. We can improve the algorithm by each process sending the max UID's only when a changed occurs(the process finds a new max UID).
My problem is The no one has mentioned the complexity bounds of these improvement. How ever I faced these problem in Nancy Lynches Distributed Algorithms book:

>     3. For the OptFloodMax algorithm, either prove a smaller upper bound than
>     O (n^3) on the number of messages or exhibit a class of digraphs and cot-
>     responding UID assignments in which the number of messages is omega(n^3)

After lots of searching in the internet and the books I couldn't find any answer to help me. I couldn't. Where does the n^3 bounds come from and which bound is the correct one?
Thanks


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If the molecular weight of two gases are ${\mathrm{M}}_{1}$ and  then at a temperature the ratio of root mean square velocity ${\mathrm{v}}_{1}$ and ${\mathrm{v}}_{2}$ will be

1. $\sqrt{\frac{{\mathrm{M}}_{1}}{{\mathrm{M}}_{2}}}$

2. $\sqrt{\frac{{\mathrm{M}}_{2}}{{\mathrm{M}}_{1}}}$

3. $\sqrt{\frac{{\mathrm{M}}_{1}+{\mathrm{M}}_{2}}{{\mathrm{M}}_{1}-{\mathrm{M}}_{2}}}$

4. $\sqrt{\frac{{\mathrm{M}}_{1}-{\mathrm{M}}_{2}}{{\mathrm{M}}_{1}+{\mathrm{M}}_{2}}}$

Explanation is a part of a Paid Course. To view Explanation Please buy the course.

Difficulty Level:


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# zbMATH — the first resource for mathematics

Dissecting the square into five congruent parts. (English) Zbl 1322.05038
Summary: We give an affirmative answer to an old conjecture proposed by Ludwig Danzer: there is a unique dissection of the square into five congruent convex tiles.

##### MSC:
 05B45 Combinatorial aspects of tessellation and tiling problems 52C20 Tilings in $$2$$ dimensions (aspects of discrete geometry)
##### Keywords:
square; dissection; five
Full Text:
##### References:
 [1] Archimedes, Ostomachion. [2] Boros, E.; Füredi, Z., Rectangular dissections of a square, European J. Combin., 9, 2, 271-280, (1988) · Zbl 0642.05016 [3] Grünbaum, B.; Shephard, G. C., Tilings and patterns, (1990), W. H. Freeman London · Zbl 0601.05001 [4] Häggkvist, R.; Lindberg, P.-O.; Lindström, B., Dissecting a square into rectangles of equal area, Discrete Math., 47, 321-323, (1983) · Zbl 0527.05022 [5] Maltby, S. J., Trisecting a rectangle, J. Combin. Theory, Ser. A, 66, 40-52, (1994) · Zbl 0797.05030 [6] Monsky, P., Dissecting a square into triangles, Amer. Math. Monthly, 77, 2, 161-164, (1970) · Zbl 0187.19701 [7] W. Moser, Research Problems in Discrete Geometry, Montreal, 1981, Problem 34. · Zbl 0528.52001
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching.


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User Manual/Appendix: Graphic filtersUser Manual/Appendix: Graphic filters

## Graphic filters

ScummVM offers several anti-aliasing filters to attempt to improve visual quality. These filters take the original game graphics, and scale it by a certain fixed factor (usually 2x or 3x) before displaying them to you. So for example, if the game originally ran at a resolution of 320x200 (typical for most of the SCUMM games), then using a filter with a scale factor of 2x will effectively yield 640x400 graphics. Likewise a 3x filter will give 960x600.

ScummVM uses the following graphic filters:

Name Factor Description Snapshot Preview
Normal 1x No filtering, no scaling, fastest
Maniac Mansion Normal
2X 2x No filtering, simple pixel duplication (default for non 640x480 games)
Maniac Mansion 2X
3X 3x No filtering, simple pixel duplication
Maniac Mansion 3X
2xSAI 2x SAI filter
Maniac Mansion 2xSAI
Super2xSAI 2x Enhanced 2xSAI filtering
Maniac Mansion Super2xSAI
SuperEagle 2x Less blurry than 2xSAI, but slower
Maniac Mansion SuperEagle
AdvMAME2x 2x Doesn't rely on blurring like 2xSAI, fast
AdvMAME3x 3x Doesn't rely on blurring like 2xSAI, fast
HQ2x 2x Very nice high quality filter but slow
Maniac Mansion HQ2x
HQ3x 3x Very nice high quality filter but slow
Maniac Mansion HQ3x
TV2x 2x Interlace filter, tries to emulate a TV
Maniac Mansion TV2x
DotMatrix 2x Dot matrix effect
Maniac Mansion DotMatrix

There is always a speed impact when using any form of anti-aliasing/linear filtering. Filters can be especially slow when ScummVM is compiled in a debug configuration without optimizations. For these reasons, not all backends support all (or even any) of the filters listed above; some may support additional ones. The filters listed above are those supported by the default SDL backend.

Note: The final resolution depends on the original resolution of the game you are playing. For example, the FM-TOWNS version of Zak McKracken uses an original resolution of 320x240, hence for this game the final resolution with a scaler will be 640x480 (2x) or 960x720 (3x). Likewise, games that were originally 640x480 (such as Curse of Monkey Island or the Broken Sword games) will be scaled to 1280x960 (2x) and 1920x1440 (3x).

## Select the Graphic Filter

### From the GUI

You can configure the Graphic Filter to use globally in the ScummVM Options (see Configuring ScummVM) or game by game, e.g. if you want for a specific game to use a different Graphic Filter than for the other games (see Configuring a game in ScummVM).

Note: When setting a graphic filter in the general ScummVM options it only applies to the games that have a low original resolution (e.g. 320x200 or 320x240). To use a graphic filter with a game that has a higher original resolution (e.g. 640x480) you need to specifically set the graphic filter in the settings for that game.

### From the Command Line

To select a graphics filter from the command line, use the '-g' option (see Command line options), e.g.:

scummvm -gadvmame2x monkey2

## Comparison

Finding the best graphic scaler is very subjective and will depend on the user. It also depends on the game as older games tended to use fewer colors and only coarse dithering.


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## Nonlinear pseudo-Boolean optimization: relaxation or propagation?

Please always quote using this URN: urn:nbn:de:0297-zib-11232
• Pseudo-Boolean problems lie on the border between satisfiability problems, constraint programming, and integer programming. In particular, nonlinear constraints in pseudo-Boolean optimization can be handled by methods arising in these different fields: One can either linearize them and work on a linear programming relaxation or one can treat them directly by propagation. In this paper, we investigate the individual strengths of these approaches and compare their computational performance. Furthermore, we integrate these techniques into a branch-and-cut-and-propagate framework, resulting in an efficient nonlinear pseudo-Boolean solver.

### Additional Services

Author: Timo Berthold, Stefan Heinz, Marc E. Pfetsch ZIB-Report Pseudo-Boolean; constraint integer programming; domain propagation; linear relaxation; separation algorithm 65-XX NUMERICAL ANALYSIS / 65Kxx Mathematical programming, optimization and variational techniques / 65K05 Mathematical programming methods [See also 90Cxx] 90-XX OPERATIONS RESEARCH, MATHEMATICAL PROGRAMMING / 90Cxx Mathematical programming [See also 49Mxx, 65Kxx] / 90C09 Boolean programming 90-XX OPERATIONS RESEARCH, MATHEMATICAL PROGRAMMING / 90Cxx Mathematical programming [See also 49Mxx, 65Kxx] / 90C10 Integer programming 90-XX OPERATIONS RESEARCH, MATHEMATICAL PROGRAMMING / 90Cxx Mathematical programming [See also 49Mxx, 65Kxx] / 90C30 Nonlinear programming 2009/03/29 ZIB-Report (09-11) 1438-0064 Appeared in: O. Kullmann (Ed.), Theory and Applications of Satisfiability Testing -- SAT 2009; Lecture Notes in Computer Science 5584, pp. 441-446, 2009

$Rev: 13581$


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# zbMATH — the first resource for mathematics

A Casorati-Weierstrass theorem for holomorphic maps and invariant $$\sigma$$-fields of homomorphic diffusions. (English) Zbl 0967.58019
The author improves the Casorati-Weierstrass theorem for holomorphic maps from some general manifolds to complex projective space. In fact the following interesting theorem is proved: No nonconstant holomorphic maps from a Kähler manifold which cannot admit nonconstant bounded harmonic functions to a complex projective space omit hyperplanes of positive measure.

##### MSC:
 58J65 Diffusion processes and stochastic analysis on manifolds 60J60 Diffusion processes
Full Text:


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## Displaying Lone Electron Pairs.

1. Perform ab initio calculations, and interface to GAMESS.
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3. Protein Data Bank is new in the traditional \$\cos^ 1.
4. It is contributed free of charge for non-commercial users.
5. Ab initio and their corresponding conformations should match yours.
6. How to use GaussView to generate and display a map of electrostatic potential ESP onto a surface of constant electron density surrounding a molecule.

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C2H2Cl2. Favorite Answer. Relevance. OGShelly. Using the geometry optimization results, high-quality images of 3D molecular structures have been prepared for Ethyne in 3 different models, namely, stick, ball & stick, and space-filling, which provide not only the basic structure information but also a physically meaningful configuration (e.g., bond lengths, bond angles, etc.) Chapter 8.Molecular Geometry and Bonding Theories (Homework) W Multiple Choice Identify the choice that best completes the statement or answers the question. Chapter 8.Molecular Geometry and Bonding Theories (Homework) W CHEM 1411. Drawing the Lewis Structure for C 2 H 2 (Ethyne or Acetylene). Ethyne (common name acetylene) is a hydrocarbon, i.e. If the formula of the compound is given, then count the number of atoms attached to each carbon and the type of bonds - single, double, or triple. Also, the angular geometry of the H-C=C bond in ethylene is 121.3 degrees. Predict the electron-pair geometry and molecular structure of the ${\text{NH}}_{4}^{+}$ cation. Click here to view hydrogen cyanide, which has linear electron group and molecular geometry. The common name for this molecule is acetylene. Click here to view acetylene (or ethyne), which has linear geometry around each … Zor Prime. 3 Chemical and Physical Properties Expand this section. Ethyne is a symmetric linear molecule, with the two carbon atoms in the center sharing a triple bond and one hydrogen on each carbon. This oxidation occurs rapidly, and the release of energy is an explosion. Acetylene (systematic name: ethyne) is the chemical compound with the formula C2H2. N2F2. Ethyne is built from hydrogen atoms (1s 1) and carbon atoms (1s 2 2s 2 2p x1 2p y1 ). Favourite answer. Phillips Petroleum is working with a new catalyst to increase production efficiency and lower cost of acetylene. By Staff Writer Last Updated Mar 27, 2020 8:54:07 PM ET. 1 Structures Expand this section. an unsaturated hydrocarbon with a triple C-C Bond. The molecular geometry of C2H4 ( ethene - an alkene ) with the skeletal structure of H2CCH2 is. Source(s): molecular geometry ethane c2h6: https://shortly.im/Qf05o. Ethyne: The distance between C and H in ethyne is about 106.0 pm. The two carbon atoms and two hydrogen atoms would look like this before they joined together: The various atomic orbitals which are pointing towards each other now merge to give molecular orbitals, each containing a bonding pair of electrons. Example 2: Predicting Electron-pair Geometry and Molecular Structure: Ammonium. molecular geometry of acetylene (or ethyne)? Ethylene, or C2H4 has two trigonal planar type molecular geometries and its center is tetrahedral. Predicting Molecular Geometry One point is earned for the correct Lewis … Triple bond is formed using sp-hybridized atoms (one s orbital is "averaged" with one p orbital). Industrial processes consume 80 percent of the acetylene produced for chemical synthesis. For C 2 H 2 you have a total of 10 valence electrons to work with.. Ethyne has a triple bond between the two carbon atoms. 25. Favorite Answer. B) 10 in bonding MOs, 2 in antibonding MOs. Answer Save. #H-C-=C-H# Answer link. When sp 3 orbitals are formed, they arrange themselves so that they are as far apart as possible. The various p orbitals (now shown in slightly different reds to avoid confusion) are now close enough together that they overlap sideways. This linear molecular geometry is similar to that of CO2 (Carbon dioxide), which is also a non-polar compound. aaj. The triple bond of the molecule stores a large amount of energy that readily oxidizes to form a more stable molecule. Ethyne, fluoro-2713-09-9. 1 decade ago. Sideways overlap between the two sets of p orbitals produces two pi bonds - each similar to the pi bond found in, say, ethene. Ethyne: There are two pi bonds in ethyne. Lancenigo di Villorba (TV), Italy. Create . Pure acetylene is odorless, but commercial grades usually have a marked odor due to impurities. The miner uses a valve to control the drip speed of water and the amount of gas produced which then burns to create light. Two of the top 50 chemicals produced in the United States, ammonium nitrate and ammonium sulfate, both used as fertilizers, contain the ammonium ion. The melting point of ethylene is −169.4 °C [−272.9 °F], and its boiling point is −103.9 °C [−155.0 °F]. When dissolved in acetone, acetylene becomes much less explosive. H 2 C = CH – CN; HC ≡ C − C ≡ CH 1 Answer Sam May 16, 2016 Linear. C2H2. 3 Answers. In the diagram each line represents one pair of shared electrons. These pi bonds are at 90° to each other - one above and below the molecule, and the other in front of and behind the molecule. Molecular Geometry of C2H2. C) 9 in bonding MOs, 3 in antibonding MOs. Organic Chemistry. Interesting note: Rotation about triple bonds is actually okay; Overlap between p orbitals is continuous enough through rotation. C) 9 in bonding MOs, 3 in antibonding MOs. Daniel P. Zaleski a, Susanna L. Stephens a, David P. Tew b, Dror M. Bittner a, Nicholas R. Walker * a and Anthony C. Legon * b a School of Chemistry, Newcastle University, Bedson Building, Newcastle-upon-Tyne, NE1 7RU, UK. 1: Download: Unmethylated | Methylated: Minor Groove Width Heat map for. In fact, we get exactly 180. Molar Mass. Figure 4. 1 decade ago. In this way there exists four Sp-orbital in ethyne. These "averaged" s and p are used for sigma-bonds (2 bonds, since there are 2 orbitals), and two p-orbitals are used for pi-bonds (also 2 bonds). Prediction of molecular polarity from bond polarity and molecular geometry. NO3^-^ FNO2. Ethane molecule is arranged in tetrahedral geometry in which central carbon atoms are surrounded by H-atoms in three dimensions. These are sigma bonds - just like those formed by end-to-end overlap of atomic orbitals in, say, ethane. Statements such as: “all hydrocarbons are nonpolar’, “the carbons are surrounded by hydrogens” or “there are no lone pairs” do not earn this … Dates: Modify . detailed explanation of the molecular geometry of acetylene? Deduction of resonance structures, examples include but are not limited to C 6 H 6 , CO 3 2- and O 3 . The basics of calculating geometry optimizations with xtb are presented in this chapter. In this text, we use the standard convention of representing multiple charges with the number before the sign, e. A quick explanation of the molecular geometry of PO43- including a description of the PO43- bond angles. In drawing the Lewis structure for C 2 H 2 (also called ethyne) you'll find that you don't have enough valence electrons available to satisfy the octet for each element (if you use only single bonds). 2 Tetrahedral shapes joined sp3 hybrids. Relevance. 3D Molecular Orbital Images of Ethyne. This is exactly the same as happens whenever carbon forms bonds - whatever else it ends up joined to. First published on 18th June 2015. Corey the Cosmonaut. What is the molecular shape of acetylene? Notice the different shades of red for the two different pi bonds. Each carbon is only joining to two other atoms rather than four (as in methane or ethane) or three (as in ethene) and so when the carbon atoms hybridise their outer orbitals before forming bonds, this time they only hybridise two of the orbitals. This article can become your one place solution as it contains the step by step guide of PCL3 molecular geometry and also the bond angles, hybridization, & the Lewis structure of the same. Construct A Model Of Ethyne By First Connecting Two Black Balls With Three Springs. 4 Answers. How Does the 25th Amendment Work — and When Should It Be Enacted? The resultant molecular structure for acetylene is linear, with a triple bond between the two carbon atoms (one sigma and two pi-bonds) and a single sigma bond between the carbon and hydrogen atoms. Ethyne . It is produced by heating either natural gas, especially its ethane and propane components, or petroleum to 800–900 °C (1,470–1,650 °F), giving a mixture of gases from which the ethylene is separated. This linear feature extends through a total of four atoms. The common name for this molecule is acetylene. Molecular Geometry: The electron pair and molecular geometries are dependent on the number of bond pairs and the lone pairs around the central atom of the molecule. C2H6 is sp3 hybridised so form Tetrahedral geometry which has all H hydrogen out of plane hence non planar. 1 decade ago. A molecule’s 3-d geometry explains a lot of its physical and chemical properties, like its polarity and intermolecular bonding behavior. C2H2 has a straight-line molecular geometry consisting of a hydrogen atom bonded to a carbon atom, which is triple-bonded to a second carbon atom bonded to a second hydrogen atom. Bond angles: HCH bond angle is 109.5 o. Since a triple bond is present and each carbon is attached to 2 atoms (1 H and 1 C), the geometry is linear. Figure 1: Steric number = 4, tetrahedral electron group geometry of H2O Figure 2: Ligand number = 2, bent molecular shape of H2O Figures 1 and 2 illustrate the difference between electron group geometry and molecular shape. The bond length for the C-H bond is 106 pm and for C-C triple bond is 120.3 pm, while the bond angle is equal to 180°. Let's also con consider, Ethyne, which is C2H2, the Lewis structure for that you may recall from our earlier work, has a triple bond between the carbon atom so we might draw it something like that. The ethane/ethyne molecule is nonpolar because the molecule is symmetric. If you have read the ethene page, you will expect that ethyne is going to be more complicated than this simple structure suggests. The various atomic orbitals which are pointing towards each other now merge to give molecular orbitals, each containing a bonding pair of electrons. The most common alkyne is ethyne, better known as acetylene. Related Searches. Lv 7. Ethyne C2H2 linear sp Hybridisation with two pi bonds. Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula C 2 H 4 or H 2 C=CH 2.It is a colorless flammable gas with a faint "sweet and musky" odour when pure. Ethyne : C 2 H 2 (a) Draw the complete Lewis electron-dot diagram for ethyne in the appropriate cell in the table above. Natural sources of ethylene include both natural gas and petroleum; it is also a hormone in plants, in which it inhibits growth and promotes leaf fall, and in fruits, in which it promotes ripening. It is a hydrocarbon and the simplest alkyne. If we look at the molecular geometry of the Ethyne molecule, you can see it here, it's a … Is tetrahedral. The molecular geometry of C2H2Br2 is trigonal planar. draw electron dot structure of ethane and butane, Common alkanes include methane (natural gas), propane (heating and cooking fuel), butane (lighter fluid) and octane (automobile fuel). If this is the first set of questions you have done, please read the introductory page before you start. Note: Explanation must refer to the shape of the molecule. The carbon atom doesn't have enough unpaired electrons to form four bonds (1 to the hydrogen and three to the other carbon), so it needs to promote one of the 2s 2 pair into the empty 2p z orbital. A colorless, highly flammable or explosive gas, C 2 H 2, used for metal welding and cutting and as an illuminant. NH2^-^ Answer Save. An example of tetrahedral electron pair geometry and molecular geometry is CH4$C$$H$$4$. •Sometimes it’s useful to describe the arrangement of atoms in terms of the molecular geometry, Contents. Acetylene forms an explosive gas in the presence of air. geometry and the ligand number. The molecular shape of the ethyne molecule is linear. The molecule is linear in geometry and shape because there are two electron groups surrounding each central C atom. The molecular geometry is a result of the combination of the individual geometries. So each carbon has 2 sigma (with C and H) and 2 … 4 Spectral Information Expand this section. Alkenes have at least one double bond and alkynes have at least one triple bond. 0 0. Bonding in Ethane. On the next page, Table 1 lists the possible molecular shapes and how they are Question: 2b) What Is The C-C-H Bond Angle In Ethene? 2021-01-02. See the lower right cell in the table above. please include the bond angles around the carbon atoms and the shape of the molecule. Monofluoroacetylene. A new molecule C 2 H 2 ⋯CuF has been synthesized in the gas phase by means of the reaction of laser-ablated metallic copper with a pulse of gas consisting of a dilute mixture of ethyne and sulfur hexafluoride in argon. Ethyne: The geometry of ethyne is linear. 2005-03-27. It is unstable in its pure form and thus is usually handled as a solution. The bigger lobe of the hybrid orbital always has a positive sign, while the smaller lobe on the opposite side has a negative sign. 2 Names and Identifiers Expand this section. More... Molecular Weight: 44.03 g/mol. 3a) The Molecule Ethyne (or Acetylene), Which Has The Molecular Formula CH.contains Two Carbon Atoms With Linear Geometry. D) 8 in bonding MOs, 4 in antibonding MOs. If the formula of the compound is given, then count the number of atoms attached to each carbon and the type of bonds - single, double, or triple. Then try to find a chemical formula that would match the structure you have drawn. And if we look at the molecular geometry for Ethyne, we discover the bond angle is around 180 degrees. Orbital overlap sketch of ethyne. Number of Pi Bonds. They are unsaturated hydrocarbon, each alkyne molecule is composed of carbon-carbon triple bond in which the carbon-carbon bonds is made up of two pi bonds and one sigma bond. These Sp-orbital are arranged in linear geometry and 180oapart. Answer Save. It is a colorless gaseous chemical compound and the simplest alkyne i.e. Ethylene is an important industrial organic chemical. Since ethyne burns with a very hot flame, one of its most notable applications is in oxyacetylene gas welding and oxyacetylene gas cutting. When ethyne is subjected to combustion with oxygen, the flame created is known to have a temperature of roughly 3600 Kelvin. Here we get about 180. Identify the electron-group geometry, molecular structure, and bond angles. Ethene consists of two sp 2 -hybridized carbon atoms, which are sigma bonded to each other and to two hydrogen atoms each. Planar N has sp2 hybrid orbitals. Ethene: There is one pi bond in ethene. Relevance. The new hybrid orbitals formed are called sp1 hybrids, because they are made by an s orbital and a single p orbital reorganising themselves. You will need to use the BACK BUTTON on your browser to come back here afterwards. This colorless gas (lower hydrocarbons are generally gaseous in nature) is widely used as a fuel and a chemical building block. In ethyne molecule, each carbon atom is Sp-hybridized. It is very reactive: the triple bond can open up for addition reactions. Lv 6. explain why ethene is a planar molecules while ethyne is a linear molecules - 17433390 Hybridization of C2H2 - Acetylene (Ethyne) Lewis Structures and Molecular Geometry: ... Ethyne has a total of 10 valence electrons, which when made to connect the constituent atoms will result to the above structure. The ethyne molecule has … Coronavirus counter with new cases, deaths, and number of tests per 1 Million population. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Ethyne, C 2 H 2. The Ethyne structure data file can be imported to most of the cheminformatics software systems and applications. According to molecular orbital (MO) theory, the twelve outermost electrons in the O2 molecule are distributed as follows: A) 12 in bonding MOs, 0 in antibonding MOs. Bond length: C-H bond length is 1.09A o and C-C bond length is 1.54A o. Please check out the chapter Singlepoint Calculations for options that are not optimization-specific, as the charge or the number of SCF iterations, for … Welding consumes the remaining 20 percent. Depending on how many other pages you might have to refer to as well, return here later using the BACK button on your browser or the GO menu or HISTORY file - or via the Organic Bonding Menu (link from the bottom of each page in this section). From this website, you can have lots of details, even a drawing of it. resonance occurs when two or more valid lewis structures may be drawn for. E) 7 in bonding MOs, 5 in antibonding MOs. NOAA Hurricane Forecast Maps Are Often Misinterpreted — Here's How to Read Them. Two sp 2 hybridized carbon atoms can make a sigma bond by overlapping one of the three sp 2 orbitals and bond with two hydrogens each and two hydrogens make sigma bonds with each carbon by overlapping their s orbitals with the other two sp 2 orbitals. Figure 1: Steric number = 4, tetrahedral electron group geometry of H2O ... ethyne (also known as acetylene, C2H2) in Figure 4. Ethene: The geometry of ethene is planar. What are Molecular Geometry and Central Atom Hybridization for . Don't confuse them with the shape of a p orbital. Drawing the Lewis Structure for C 2 H 2 (Ethyne or Acetylene). lie perpendicular to … For C 2 H 2 you have a total of 10 valence electrons to work with.. The molecular geometry is a result of the combination of the individual geometries. Acetylene is a common gas for fueling welders' oxyacetylene torches. it is built from only carbon and hydrogen atoms. They use the 2s electron and one of the 2p electrons, but leave the other 2p electrons unchanged. The shape of the molecule can be predicted if hybridization of the molecule is known. The LibreTexts libraries are Powered by MindTouch ® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. Old carbide miner's lamps use this reaction to create light. Ethylene, the simplest of the organic compounds known as alkenes, which contain carbon-carbon double bonds. Find out A to Z information of PCL3 (i.e.) Try This: Give the hybridization states of each of the carbon atoms in the given molecule. Ethyne is built from hydrogen atoms (1s1) and carbon atoms (1s22s22px12py1). To understand ethene you also have to understand orbitals and the bonding in methane - sorry, there are no short-cuts! 8 Simple Ways You Can Make Your Workplace More LGBTQ+ Inclusive, Fact Check: “JFK Jr. Is Still Alive" and Other Unfounded Conspiracy Theories About the Late President’s Son. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds).. C2H2 has a straight-line molecular geometry consisting of a hydrogen atom bonded to a carbon atom, which is triple-bonded to a second carbon atom bonded to a second hydrogen atom. Fact Check: Is the COVID-19 Vaccine Safe? The shape of methane. For example, an atom with four single bonds, a double bond, and a lone pair has an octahedral electron-group geometry and a square pyramidal molecular structure. So, keep calm and know about the geometry of … The gas cylinders one finds in welding shops contain this acetylene-acetone solution under pressure. The gross formula is C_2H_2. E) 7 in bonding MOs, 5 in antibonding MOs. There is a triple bond between the two carbon atoms, each having one valency left for the hydrgen atoms: H-C-=C-H Since the triple bond prevents rotation, the ethyne molecule is linear. Calcium carbide reacts with water to produce acetylene. Ethyne has a triple bond between the two carbon atoms. In this manner, what hybridization is c2h2? Lv 7. 47% H, … The sigma bonds are shown as orange in the next diagram. C 2 H 2 Molecular Geometry And Bond Angles As a result of the double bond C 2 H 2 molecular geometry is linear with a bond angle of 180 o . Answers will vary. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds).. Use Two Short Sticks And Two Yellow Balls To Complete The Structure. Nothing changes in terms of the shape when the hydrogen atoms combine with the carbon, and so the methane molecule is also tetrahedral with 109.5° bond angles. Ethene: The molar mass of ethene is about 28 g/mol. Molecular Geometry •Being able to predict the electron group geometry around an atom is useful because it allows us to predict the approximate bond angles and guides us in drawing the geometric sketch. Also called ethyne. Phosphorus Trichloride here. Explanation of the properties of giant covalent compounds in terms of their structures. The simple view of the bonding in ethyne. Ethyne (acetylene) is linear. Subsequently, question is, what does c2h2 stand for? it … Is C2H2 Polar Or Nonpolar? So, here we got about 120. The carbon atom doesn't have enough unpaired electrons to form four bonds (1 to the hydrogen and three to the other carbon), so it needs to promote one of the 2s2 pair into the empty 2pz orbital. 1 decade ago. The molecular shape is determined by the electron group geometry and the ligand number. Ethyne, (commonly known as Acetylene), is a chemical compound with the molecular formula C2H2. Chemical formula of Ethyne. including the bonds and hyrbidizations? Distortions of ethyne when complexed with a cuprous or argentous halide: the rotational spectrum of C 2 H 2 ⋯CuF†. Molecular geometry (trigonalpyramid) ... Ethyne, C 2H 2 •Ethyne (often called acetylene) has two central atoms, so we consider them separately. Related questions. •They each have two electron groups around them: one single bond and one triple bond. The remaining unhybridized p orbitals on the carbon form a pi bond, which gives ethene its reactivity. D) 8 in bonding MOs, 4 in antibonding MOs. That is a tetrahedral arrangement, with an angle of 109.5°. Ethyne or acetylene, HC=CH, is the simplest alkyne example. Ethylene is a gas known to chemist since second half of XIX century. According to molecular orbital (MO) theory, the twelve outermost electrons in the O2 molecule are distributed as follows: A) 12 in bonding MOs, 0 in antibonding MOs. How do I determine the molecular shape of a molecule? In drawing the Lewis structure for C 2 H 2 (also called ethyne) you'll find that you don't have enough valence electrons available to satisfy the octet for each element (if you use only single bonds). what is the hybridization of the carbon atoms in a molecule of ethyne represented above, Carbon hybridization in Ethylene—C 2 H 4. Explanation: Acetylene has two electron domains around the carbon atoms. Acetylene use is growing due to the demand for more of the gas in production of polyethylene plastics. Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula C 2 H 4 or H 2 C=CH 2.It is a colorless flammable gas with a faint "sweet and musky" odour when pure. The U.S. Supreme Court: Who Are the Nine Justices on the Bench Today? Answer. These are sigma bonds - just like those formed by … at the lowest energy level. Molecular Geometry. And if we look at the molecular geometry for Ethyne, we discover the … Generally, acetylene is used as a fuel and a chemical building block. In the ethane molecule, the bonding picture according to valence orbital theory is very similar to that of methane. 3 Answers. What these look like in the atom (using the same colour coding) is: Notice that the two green lobes are two different hybrid orbitals - arranged as far apart from each other as possible. Furthermore, ethyne is a hydrocarbon or a compound containing only C-H bonds. B) 10 in bonding MOs, 2 in antibonding MOs. Geometry Optimization ¶. What are the Uses of Ethyne? thanks. 25. What is the molecular geometry of ethylene? Just like those formed by end-to-end overlap of atomic orbitals in, say ethane. Acetylene-Acetone solution under pressure due to the demand for more of the individual geometries the skeletal of... This colorless gas ( lower hydrocarbons are generally gaseous in nature ) a. The melting point of ethylene is an important industrial organic chemical 1s22s22px12py1 ) complexed with a new catalyst increase... Not limited to C 6 H 6, CO 3 2- and o.. Created is known to chemist since second half of XIX century, 1525057, and number tests. Mos, 3 in antibonding MOs this simple structure suggests bonding picture according to valence theory! -Hybridized carbon atoms around the carbon atoms 8:54:07 PM ET C-H bonds its pure and! 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text:
# Tag Info

Accepted

### Is regular CTR mode vulnerable to any attacks?

Summing up the discussion in the comments: What you are describing is the CTR Mode of operation of block ciphers, which requires an encryption function ("E" in your diagram) like AES. So, "should I ...
• 1,420
Accepted

### What does a stream cipher provide that cannot be obtained with AES CTR mode operation?

AES-CTR is a stream cipher, of a particular kind where the keystream is obtained by encryption of a counter. So the question reduces to: what are drawbacks of AES-CTR compared to other stream ciphers? ...
• 128k
Accepted

### What are the risks of using CTR mode with 64 bit blocks?

I believe that he was referring to the misconception that the birthday problem that arises in encryption is only when you use the same counter twice. If a random IV is used, then such a counter ...
• 27.1k
Accepted

Disadvantages: Message length: In Cryptography, usually, the message length is not considered secret. There are approaches that you can add random values to the end or beginning or both if this is ...
• 45.2k
Accepted

### Can we use a sort of "hash" function in CTR mode instead of a block cipher?

Your intuition is on the right track: if you run a pseudorandom function in counter mode with your secret key, you get a stream cipher. Some stream ciphers are designed like this, perhaps most ...
• 14.1k
Accepted

### Can I use MAC as CTR mode nonce, if my messages are non-repeating?

Yes, but to use a known algorithm that specifies precisely that, take a look at the SIV mode of operation . "SIV" stands for Synthetic IV. IV is the initialization vector, which is the nonce ...
• 87.1k
Accepted

### Relationship between AES GCM and AES CTR

That's correct. In most cases you can do what you are proposing. However be warned that by disregarding the authentication you clearly loose message authentication and bit flipping in AES-CTR ...
• 6,559
Accepted

### Would an encryption-only block cipher be useful at all?

Would it make any sense to design an irreversible block cipher where the encryption side wouldn't be reversible (and thus you can't implement decryption), Block cipher is a synonym for Pseudo Random ...
• 45.2k

### mode of operation in cryptography

I would pick e) none of the above. None of those modes offers integrity protection, so unless integrity is handled elsewhere, your application is wildly insecure. An attacker could modify bits in ...
• 37.9k

### mode of operation in cryptography

You would not just need a mode of operation for what you're asking. What you need is a secure transport protocol. Probably the best well known one for TCP connections is TLS of course. For UDP ...
• 87.1k
Accepted

### Counter mode with $\operatorname{AES}_k(m)$ vs $\operatorname{AES}_m(k)$

I understand that it would be quite inefficient as the key schedule would need to be re-calculated for every block, but would it make cryptanalysis easier? It would make cryptanalysis trivial. If ...
• 136k

### Why isn't CTR mode (counter mode) used more often?

There are probably quite a few good reasons for this, although I don't expect that a scientific answer can be composed (as you would need to use a survey, and I've never heard of such a thing for ...
• 87.1k

### How to Implement Deterministic Encryption Safely in .NET

You can safely use HMAC-SHA256 instead of the SIV mode custom PRF to derive the nonce/authentication tag. There's some caveats: HMAC-SHA256 gives a 256-bit output; you'll have to truncate it to the ...
• 46.5k
Accepted

### Does AES CTR mode store header information in encrypted files?

I would like to ask if that is true for every AES CTR mode implementation?, Doesn't have to be. You can store the nonce anywhere. You could even send it to the recipient via a different channel (e.g....
• 37.9k
Accepted

### Implementing 5 modes of operation with a hash function

The modes you are referencing are specifically modes of operations for block ciphers, and therefore are not directly applicable to hash functions. Block cipher operations take 2 inputs, the key and a ...
• 12.8k
Accepted

### Using checksum instead of hash for authenticating ciphers

If we were to use CTR, what would you think of using a checksum on plain text then encrypt whole. That's a really bad idea (from a security perspective). Here are the reasons for this: Depending ...
• 45k
Accepted

Yes, there is an important one; The Non-Repudiation; Non-repudiation refers to a situation where a statement's author cannot successfully dispute its authorship or the validity of an associated ...
• 45.2k
Accepted

### Are all stream-ciphers IND-CPA?

No. There is a difference between the type of a cipher and the construction of a cipher. If a cipher is of a specific type for which there are known IND-CPA secure constructions then that doesn't ...
• 87.1k

### Does CTR mode yield a PRF?

It is not accurate to say that the keystream from AES-CTR is a pseudorandom function. However, it is a pseudorandom generator. Furthermore, the construction that you gave is close to working but it's ...
• 27.1k

### AES decryption vs encryption speed

Given the choice, it is preferable to use the block encryption operation of AES, since it often faster than block decryption (never slower AFAIK). For this reason, AES-CTR is defined to use the block ...
• 128k

### How is decryption done in AES CTR mode?

A slight correction about terminology: The key is constant when you use CTR. The IV/counter affect the cipher input and so the keystream varies. The reason this can be decrypted is that the ...
• 31.5k
Accepted

### CPA-security of CTR mode

One gap in your proposed argument is that $ctr$ is known to the adversary (it is included in the ciphertext), whereas saying "$G_k(ctr)$ is pseudorandom" implicitly assumes that both $k$ and $ctr$ are ...
• 5,672
Accepted

### Can I create a random access CSPRNG from a hash?

There is a name for "random access PRG" : it's called a pseudorandom function (PRF). Any block cipher is a pseudorandom function (that's more-or-less the definition of what it means to be a secure ...
• 11.1k

### What are the risks of using CTR mode with 64 bit blocks?

This answer summarizes what's achieved against CTR mode in the paper pointed by Yehuda Lindell's answer: Gaëtan Leurent and Ferdinand Sibleyras's The Missing Difference Problem, and its Applications ...
• 128k
Accepted

### Hashing a counter to prevent distinguishers in CTR mode

I'm reading the question as generating a keystream per: $S_i\gets E_K(F(\mathrm{IV},i))$ where $F$ is a public function built from a hash function; for incremental index $i$ starting from $0$ and ...
• 128k
Accepted

### Is it safe to reuse the password when using AES-CTR with scrypt?

CTR is insecure if you reuse a key/iv pair. Since the salt is random, a different encryption key will be derived every time you encrypt something. Therefore it is safe even if it always uses the zero ...
• 6,189

### What does a stream cipher provide that cannot be obtained with AES CTR mode operation?

First, AES-CTR isn't "similar to a stream cipher." It is a stream cipher. That means the real question is "why do we develop new stream ciphers when AES-CTR provides an acceptable one?" The answer is ...
• 3,567
Accepted

### Turning a 64 bit block cipher into a 128 bit block cipher

There are two well-known Encryption modes, that can construct a $mn$-bit tweakable blockciphers from a $n$-bit blockcipher ($n=64$ for DES) with $1\le m\le n$. The older one is CMC, being not ...
• 45k
Accepted

### Why is it good to split a CTR-mode counter into nonce and counter?

Suppose you do CTR mode as: $E(k,nonce+1) \oplus m_1$, $E(k,nonce+2) \oplus m_2$, $E(k,nonce+3) \oplus m_3$, etc. The wikipedia page is talking about a non-random nonce, with a specific example of ...
• 11.1k
Accepted

### Using HMAC as a nonce with AES-CTR encrypt-and-MAC

What you're describing is pretty similar to the SIV block cipher mode. It also uses a deterministic function of the message to derive the nonce for CTR encryption. Under some pretty widely accepted ...
• 4,576

Only top scored, non community-wiki answers of a minimum length are eligible


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# Virial Theorem derivation

1. Jan 17, 2008

### Himanshu

Can somebody explain me how does the derivation for <K>=-<delta(U)> goes under the viral theorem?

2. Jan 17, 2008

### smallphi

1.They define something called called 'scalar moment of inertia around the origin', I. It looks similar to moment of inertia around an axis in mechanics but not quite.

2. The first derivative G = (1/2) dI/dt is called 'virial'. They prove that the first derivative of the virial, dG/dt, i.e. the second time derivative of I , depends on the total kinetic energy T of the system and the potential energy U, when the potential energy is a power law ~ r^n:

dG/dt = 2T - nV (n=-1 for gravity)

3. They take the time average <...> of the above equation and claim that after long time the system 'virializes' so that the time average <dG/dt> = 0 which gives you an equation between the time averages of kinetic energy and potential energy:

<T> = (n/2) <V>

4. If we assume the system is 'virialized' i. e. in a stationary state, equilibrium, so that the total kinetic and potential energy do not change with time, the time averages will equal the energies at any time.

When that theorem is applied in astronomy, we measure/observe only the total kinetic and potential energies at a given time. We don't have access to time averaged values because the times involved are millions/billions of years but we assume the system is virialized already so the energy values equal the time averages.

All that (except point 4) can be found here http://en.wikipedia.org/wiki/Virial_theorem

Last edited: Jan 17, 2008
3. Jan 18, 2008

Thanks!


text:
👂 Active learning for text classification with small-text#

In this tutorial, you will learn how to set up a complete active learning loop with a Hugging Face transformer:

• Use the excellent small-text library to set up your active learner;

• Use a Argilla listener to build and start an active learning loop;

• Use the Argilla UI to annotate examples and learn actively;

Introduction#

Active learning is a special case of machine learning in which a learning algorithm can interactively query a user (or some other information source) to label new data points with the desired outputs. Wikipedia

Supervised machine learning often requires large amounts of labeled data that are expensive to generate. Active Learning (AL) systems attempt to overcome this labeling bottleneck. The underlying idea is that not all data points are equally important for training the model. The AL system tries to query only the most relevant data from a pool of unlabeled data to be labeled by a so-called oracle, which is often a human annotator. Therefore, AL systems are usually much more sample efficient and need far less training data than traditional supervised systems.

This tutorial will show you how to incorporate Argilla into an active learning workflow involving a human in the loop. We will build a simple text classifier by combining the active learning framework small-text and Argilla. Hugging Face’s transformers will provide the classifier we will embed in an active learner from small-text. Argilla excels in making you the oracle that conveniently teaches the model via an intuitive UI.

Setup#

For this tutorial, we also need some optional and third-party libraries that you can install via pip:

[ ]:

%pip install "argilla[listeners]" "datasets~=2.5.0" "small-text>=1.1.0"  "transformers[torch]"

The TREC dataset#

For this tutorial, we will use the well-known TREC dataset containing 6000 labeled questions; 5500 in the training and 500 in the test split. This dataset can be turned into a text classification task, in which a model must predict one of the six coarse labels given the question. The labels consist of ABBREVIATION (ABBR), ENTITY (ENTY), DESCRIPTION (DESC), HUMAN (HUM), LOCATION (LOC), and NUMERIC VALUE (NUM).

Let us load the dataset from the Hugging Face Hub:

[ ]:

import datasets

Preprocessing the dataset#

We first need to wrap the dataset in a specific data class provided by small-text, the excellent active learning framework we will use in this tutorial. Since we will choose a Hugging Face transformer in the active learner, small-text will expect a TransformersDataset object that already contains the tokenized input text.

In order to build a TransformersDataset object, we first need a tokenizer:

[ ]:

import torch
from transformers import AutoTokenizer

# Choose transformer model: In non-gpu environments we use a tiny model to reduce the runtime
if not torch.cuda.is_available():
transformer_model = "prajjwal1/bert-tiny"
else:
transformer_model = "bert-base-uncased"

# Init tokenizer
tokenizer = AutoTokenizer.from_pretrained(transformer_model)

With this, we can create a TransformersDataset by calling TransformersDataset.from_arrays() which expects a list of texts, a numpy array (which indicates single-label classification), a tokenizer, and lastly the possible (integer values) of target labels within this dataset.

[ ]:

import numpy as np
from small_text import TransformersDataset

num_classes = trec["train"].features["coarse_label"].num_classes
target_labels = np.arange(num_classes)

train_text = [row["text"] for row in trec["train"]]
train_labels = np.array([row["coarse_label"] for row in trec["train"]])

# Create the dataset for small-text
dataset = TransformersDataset.from_arrays(
train_text, train_labels, tokenizer, target_labels=target_labels
)

We will also create a test dataset to track the performance of the transformer model during the active learning loop.

[ ]:

# Create test dataset
test_text = [row["text"] for row in trec["test"]]
test_labels = np.array([row["coarse_label"] for row in trec["test"]])

dataset_test = TransformersDataset.from_arrays(
test_text, test_labels, tokenizer, target_labels=np.arange(num_classes)
)

Setting up the active learner#

Now that we have our datasets ready let’s set up the active learner. For this, we need two components:

• the classifier to be trained;

• the query strategy to obtain the most relevant data;

In our case, we choose a Hugging Face transformer as the classifier and a tie-breaker as the query strategy. The latter selects instances of the data pool with a small margin between the two most likely predicted labels.

[ ]:

import logging

from small_text import (
BreakingTies,
PoolBasedActiveLearner,
TransformerBasedClassificationFactory,
TransformerModelArguments,
)

# Set logger to get training feedback
logging.getLogger("small_text").setLevel(logging.INFO)

# Define our classifier
clf_factory = TransformerBasedClassificationFactory(
TransformerModelArguments(transformer_model),
num_classes=6,
kwargs={"verbosity": 100}
# If you have a cuda device, specify it here.
# Otherwise, just remove the following line.
# kwargs={"device": "cuda"}
)

# Define our query strategy
query_strategy = BreakingTies()

# Use the active learner with a pool containing all unlabeled data
active_learner = PoolBasedActiveLearner(clf_factory, query_strategy, dataset)

Since most query strategies, including ours, require a trained model, we randomly draw a subset from the data pool to initialize our AL system. After obtaining the labels for this batch of instances, the active learner will use them to create the first classifier.

[ ]:

from small_text import random_initialization
import numpy as np

# Fix seed for reproducibility
np.random.seed(42)

# Number of samples in our queried batches
NUM_SAMPLES = 20

# Randomly draw an initial subset from the data pool
initial_indices = random_initialization(dataset, NUM_SAMPLES)

Argilla and you: the perfect oracle#

With our active learner ready, it is time to teach it. We first create a Argilla dataset to log and label the initial random batch queried by the active learner.

[ ]:

import argilla as rg

# Choose a name for the dataset
DATASET_NAME = "trec_with_active_learning"

# Define labeling schema
labels = trec["train"].features["coarse_label"].names
settings = rg.TextClassificationSettings(label_schema=labels)

# Create dataset with a label schema
rg.configure_dataset(name=DATASET_NAME, settings=settings)

# Create records from the initial batch
records = [
rg.TextClassificationRecord(
text=trec["train"]["text"][idx],
id=idx,
)
for idx in initial_indices
]

rg.log(records, DATASET_NAME)

Before switching to the Argilla UI to label the records, we will set up the active learning loop. For this, we will use the listener decorator from Argilla. The loop will run automatically once all records of a batch are labeled (see the query and condition argument of the decorator). It will trigger the classifier’s training, query a new batch from the active learner and log it to Argilla. We will also keep track of the accuracy of the current classifier by evaluating it on our test set.

[ ]:

from argilla.listeners import listener
from sklearn.metrics import accuracy_score

# Define some helper variables
LABEL2INT = trec["train"].features["coarse_label"].str2int
ACCURACIES = []

# Set up the active learning loop with the listener decorator
@listener(
dataset=DATASET_NAME,
condition=lambda search: search.total == NUM_SAMPLES,
execution_interval_in_seconds=3,
batch_id=0,
)
def active_learning_loop(records, ctx):
# 1. Update active learner
print(f"Updating with batch_id {ctx.query_params['batch_id']} ...")
y = np.array([LABEL2INT(rec.annotation) for rec in records])

# initial update
print(
"Starting training! Depending on you device, this might take a while, so set up"
" logging."
)
if ctx.query_params["batch_id"] == 0:
indices = np.array([rec.id for rec in records])
active_learner.initialize_data(indices, y)
# update with the prior queried indices
else:
active_learner.update(y)
print("Done!")

# 2. Query active learner
print("Querying new data points ...")
queried_indices = active_learner.query(num_samples=NUM_SAMPLES)
new_batch = ctx.query_params["batch_id"] + 1
new_records = [
rg.TextClassificationRecord(
text=trec["train"]["text"][idx],
id=idx,
)
for idx in queried_indices
]

# 3. Log the batch to Argilla
rg.log(new_records, DATASET_NAME)

# 4. Evaluate current classifier on the test set
print("Evaluating current classifier ...")
accuracy = accuracy_score(
dataset_test.y,
active_learner.classifier.predict(dataset_test),
)

ACCURACIES.append(accuracy)
ctx.query_params["batch_id"] = new_batch
print("Done!")

print("Waiting for annotations ...")

Starting the active learning loop#

Now we can start the loop and switch to the Argilla UI.

[ ]:

active_learning_loop.start()

In the Argilla UI, we will set the number of records per page to 20 since it is also our chosen batch size. Furthermore, we will use the Status filter to filter out already annotated records. Now, all we have to do is to annotate the displayed records. Once annotating everything, the classifier’s training will be automatically triggered.

After a few seconds, you should see the newly queried batch when pressing the Refresh button. The training can take longer depending on your machine and whether you have a CUDA device. You can always check the status of the active learning loop from your notebook.

Can we stop?#

After a few iterations, we can check the accuracy of the current classifier and plot its evaluation.

[ ]:

import pandas as pd

pd.Series(ACCURACIES).plot(xlabel="Iteration", ylabel="Accuracy")

We should achieve an accuracy of at least 0.8 after around 12 iterations, corresponding to roughly 260 annotated records. The stopping criterion is ultimately up to you, and you can choose more sophisticated criteria like the KappaAverage implemented in small-text.

[ ]:

active_learning_loop.stop()

Summary#

In this tutorial, we saw how you could embed Argilla in an active learning loop involving a human in the loop. We relied on small-text to use a Hugging Face transformer within an active learning setup. In the end, we gathered a sample-efficient data set by annotating only the most informative records for the model.

Argilla makes it very easy to use a dedicated annotation team or subject matter experts as an oracle for your active learning system. They will only interact with the Argilla UI and do not have to worry about training or querying the system. We encourage you to try out active learning in your next project and make your and your annotator’s life a little easier.


text:
# Kepler's 3rd Law

Students derive the velocity in a circular orbit of any radius. They derive the Earth escape velocity and prove Kepler's 3rd law for circular orbits # A simple formula for the orbital period in a circular Earth orbit of given radius.