New Year Resolution

There are only a few hours in year 2010. Before the new year begins, I am going to make new year’s resolutions here.

1. Finishing my PhD study.

2. Finding a job.

3. Publishing at least one paper of my work.

4. Practicing writing skills through blogging every week.


Books about Superabsorbent Polymer

If we are talking about superabsorbent polymer (SAP), we could not ignore the most famous book Modern Superabsorbent Polymer Technology edited by Fredreic L. Buchholz, and Andrew T. Graham from Dow Chemical. It gives a comprehensive review on the structure, properties, and applications of SAPs. In this book, the properties of SAPs varies with the synthesis chemistry has been discussed. Also, the comparison of industrial practices between major manufactures has been done. The analytical methods to evaluate the properties and behaviors of SAPs also were described within the context. New SAP products were introduced, too. Besides, the current and emerging applications of SAPs in personal care, horticulture, construction, and other areas have been mentioned. What a pity three is nothing about the applications of SAPs in oil and gas industry, what I have been done for a couple of years. Maybe because the book was born too early to cover this new application.

There are another two books in which an individual chapter reviewed the SAPs: Encyclopedia of Polymer Science and Technology(Vol. 8), and Ullmann’s Encyclopedia of Industrial Chemistry. Since both of the two sources only have around 20 pages, I prefer to the latter one, because which provided more well organized words.

LaTeX Tricks (2)

I have been working on my dissertation using LaTeX for one week. Most of the contents came from my proposal. Now the structure has been set up and it is around 40 pages already. The next step is to fill the blanks. During the time period, I solved some problems by some tricks found on the Internet.

1. Upper or Lower case:
It is very easy to write upper or lower case in LaTeX. The cubic meter could be written as m^3 by $m^3$, but the display is mathematical, and the letters shows italics. If add \text in front of the code as \text m^3, the normal font appeared[1].

2. Multi-row Table:
Sometimes we need special tables. Multirow (multicolumn) command provide more choices.
Here is one simple example:
\centering \caption[Particle Size Distribution of
$\text{LiquiBlock}^{\texttrademark}$ 40K]{Particle Size Distribution
of $\text{LiquiBlock}^{\texttrademark}$ 40K}
\multirow{2}*{Mesh} & Size & Weight& Percentage \\
& (mm) & (g)& (\%) \\
18 & 1.000 & 9.14 & 2.29 \\
20 & 0.850 & 134.95 & 33.85 \\
30 & 0.600 & 134.21 & 33.66 \\
40 & 0.425 & 63.25 & 15.86 \\
45 & 0.355 & 20.85 & 5.23 \\
50 & 0.300 & 16.91 & 4.24 \\
60 & 0.250 & 14.90 & 3.74 \\
70 & 0.212 & 0.14 & 0.04 \\
$<$70 & $<$0.212 & 4.34 & 1.09 \\
It seems that wordpress does not support Table function of LaTeX. Please see the snapshot of the table below.

3. No Indent
Sometimes the journal requires no indent at the beginning of each paragraph[2].


1. How to change the font of upper case into normal font.
2. No Indent.

LaTeX Tricks (1)

Last night a simple version of my dissertation has been created by LaTeX. As a fresh hand in LaTeX, there are so many things to learn, especially the tricks. A short summary for my work last night could be found below:

  • Convert the .jpg file to .eps file:

LaTeX supports .eps files very well. It is possible to insert jpg pictures into LaTeX, also. From my experience last night, .jpg files maybe troublesome for LaTeX. Image-Pro Plus has ever been used to convert .jpg files into .eps files. Also, HP LaserJet 6P/6MP PostScript printer could do this job. Finally, I found another easy way. Now most TeX software embedded such kind of tools as bmeps.exe.[1] Type the following command under DOS mode in the folder where .jpg files are saved:

X:\bmeps *.jpg *.eps -c(if no -c, black and white pictures were generated).

  • Insert .eps files in LaTeX

As previous description, LaTeX supported .eps files for a long time, and they linked with each other very well. All the textbooks about LaTeX just gave a brief instruction on how to insert .eps files in LaTeX. But, when I was trying to do the same thing following the instruction, the results disappointed me. After having done research on the Internet, I found latexpdf command could not read .eps files.[2] The solution is to compile the TEX files using latex command, then convert. dvi files into pdf using dvipdf command.

And another webpage I found last night provides more LaTeX tricks, which is kept here for future use.[3]


1. Print .jpg files to .eps files (Chinese).
2. Problems during inserting .eps files into LaTeX(Chinese).
3. LaTeX tricks.

Converters from LaTeX to PC Textprocessors – Overview (by Wilfried Hennings)

Note: I determined to learn LaTeX around 5 years ago. At that time, a friend of mine gave me a book about how to use LaTeX. I also found some resources on the Internet. But due to limited use for my research and work, I do not have a chance to focus on it. LaTeX has so many advantages over other word processors like Microsoft Word. The relationship between LaTeX and Word is similar to that between keyboard and mouse. Mouse makes the operation easier, but keyboard is much more important and necessary. For common users, Word could satisfy their needs, but the equations and batch operations need LaTeX. In previous pages here, I insert some equations with LaTeX codes supported by WordPress. Because people around me do not use LaTeX very often, I had to find a way to convert my LaTeX files into Microsoft Word to exchange my ideas about research and work. Google found the useful information for me. In this blog, I forwarded an overview on converters between LaTeX and PC word processors for your and my own references.

Converters from LaTeX to PC Textprocessors – Overview

Switch conversion direction: From PC to LaTeX

Author: Wilfried Hennings (texconvfaq “at”, this page last updated on Oct. 6, 2009
The url of this page is

I maintain these pages because I need converters between LaTeX and PC Textprocessors for my work and I want to share the information with others who need it. Because I maintain them in my spare time (uh, what is spare time?), I can not answer individual questions.

This list is as good or as bad as its support, and it needs YOUR support to update and supplement this list. Please supplement if you know more and/or better ones. There are some more converters on the CTAN sites, but the following seem to be most promising for conversion to and from the current versions of wordprocessors.

Neither correctness nor completeness is guaranteed.
All opinions mentioned (if any) are my own. Please send corrections, enhancements and supplements (auch in deutscher Sprache) to the following address:
texconvfaq “at”

Note that this FAQ list contains information about converters ONLY between LaTeX and PC word processors. Converters to and from other formats may have own FAQ lists – e.g. see the link for converters to and from HTML.

For the impatient, here is a table with overview of features of the most recent converters.

General Remarks

Before looking for a converter, stop and think about a principal question:

What do you want to be converted in which way?

Do you want to convert the document structure, i.e. a heading should remain a heading, a list should remain a list etc., no matter how it will look like in the target format?
Or do you want to convert the appearance, i.e. how it looks like, no matter how it is represented in the target format?
Or do you want a mixture of both?
For using SGML as an intermediate format, you would have to specify the translation rules yourself (as far as I understood). This makes sense, and explains why different people have very different opinions about which converter best fits their needs: They simply have different demands and expectations on what should be converted and how.
So, not only practically there is no converter which is good for everyone and every purpose, but this is even principally impossible because there are no well-defined requirements which a converter should meet.

An additional problem is that TeX/LaTeX can be extended by an unlimited number of macros. Unless the converter contains a full-scale TeX system, it can at best support the publicly available macro commands, not the ones privately written by individual users. Practically you can expect that it supports the standard LaTeX commands and perhaps a few more widely used packages. The only converter which uses a full-scale TeX system is TeX4ht.

So keep this in mind when looking through the following list of converters, try yourself and decide what you need.

There are several ways to convert.

To illustrate these, let me restrict it to the Microsoft Word case:

  • directly type or paste LaTeX code into Word
  • use a Word import filter
  • use a Word macro: load LaTeX file as plain text, then search for LaTeX markup and replace the markup by formatting, special characters and equations.
  • use an external converter:
  1. LaTeX -> RTF, then use Word’s own RTF import,
  2. LaTeX -> HTML, then use Word’s internet assistant or built-in html converter,
  3. maybe other external format(s).

The converters being most complete and currently maintained / supported are:

TeX2Word – a shareware LaTeX import filter for MS Word

GrindEQ – a shareware LaTeX import filter for MS Word

latex2rtf – a free standalone LaTeX -> RTF converter for PC, Macintosh and Unix,

TexPort – a commercial TeX/LaTeX to WordPerfect and Microsoft Word converter for PC.

TeX4ht – a free LaTeX to html or XML converter for PC and Unix produces html which is good for loading into Word. TeX4ht relies on other software, it needs at least a full TeX system.

There are also converters to Powerpoint and to FrameMaker (see further below).

Directly type or paste LaTeX code into Word

All of these only allow typing or pasting LaTeX coded equations in Word, not LaTeX coded text elements.

“Aurora” (formerly named Ribbit) can now convert a LaTeX coded equation (which must be placed on the Windows clipboard) to Word. The converter is still experimental and as such has a number of limitations, some of which will be addressed in future releases. The converter’s output will generally need some manual touching up to achieve the level of fidelity on a par with the original document.
The other functionality of Aurora, which was the only functionality of its predecessor “Ribbit”, is letting you enter LaTeX equations in word processors such as MS Word or in Powerpoint. One can enter the equation in LaTeX markup, and the formatted equation is inserted as an object.
See homepage (external link) (Shareware)
Aurora needs a working LaTeX installation. If there is no, it will install a micro version of MiKTeX.

“LaTeX in Word”: See homepage (external link) (Freeware, GPL).
It allows to enter LaTeX equations in word processors such as MS Word in LaTeX markup, and the formatted equation is inserted in the Wordprocessor as a png bitmap. It needs a server which performs the conversion. Server installation files are available from the download page (external link).

MathType (external link) allows typing and pasting equations in LaTeX markup.

OpenOffice allows typing equations in LaTeX-like markup.

Word 2007 allows typing equations in LaTeX-like markup (although not 100% compatible), see

Use a Word import filter

TeX2Word: Shareware, 99$ (45$ academic).
Current version: 2.5, released April 2008.
Support for more document styles and packages will be available with future versions. You can also supply support for document styles, packages and user defined macros by yourself (needs TeX programming knowledge).
* MS Windows 95 or later (NT4, ME, Win2000, WinXP),
* MS Word 95 or later (97, 2000, XP) and
* MathType (external link) 4 or later (full version of the Equation Editor which comes with MS Word).
See homepage (external link)

GrindEQ LaTeX-to-Word: Shareware, 99EUR (49EUR academic).
converts LaTeX, AMS-LaTeX, Plain TeX, or AMS-TeX documents to Microsoft Word format.
You can choose the following formats for TeX/LaTeX equations: Microsoft Equation 2007, Microsoft Equation 3.x, or MathType.
Works with Microsoft Word 97/2000/XP/2003/2007 and Microsoft Windows 98/Me/NT/2000/XP/2003/x64/Vista.
Evaluation version is restricted to 10 launches.
See homepage (external link)

Convert to RTF


latex2rtf: LaTeX-to-RTF-converter. See the more detailed page.

Convert to WordPerfect format


TexPort converts your TeX and LaTeX files to WordPerfect or Microsoft Word documents.
See more detailed page
See home page (external link)

Use a Word macro


tex2doc by Thomas Link (external link): LaTeX to WinWord 6 and WinWord 7(95) converter, written as Word macros. Also attempts to convert tables! Not compatible with Word 2000 and up, no further development.
homepage (external link),

ltx2word, by myself: LaTeX to WinWord 6, WinWord 7(95) and WinWord 97 converter, written as Word macros. No tables. Not compatible with Word 2000 and up, no further development.
See more detailed page.

Use a Word add-in

The following are no full converters but only allow typing or pasting LaTeX code into Word:

“Aurora” (formerly named Ribbit) can now convert LaTeX code (which must be placed on the Windows clipboard) to Word. The converter is still experimental and as such has a number of limitations, some of which will be addressed in future releases. The converter’s output will generally need some manual touching up to achieve the level of fidelity on par with the original document.
The other functionality of Aurora, which was the only functionality of its predecessor “Ribbit”, is letting you enter LaTeX equations in word processors such as MS Word or in Powerpoint. One can enter the equation in LaTeX markup, and the formatted equation is inserted as an object.
See homepage (external link) (Shareware)
Aurora needs a working LaTeX installation. If there is no, it will install a micro version of MiKTeX.

“LaTeX in Word”: It allows to enter equations in word processors such as MS Word in LaTeX markup, and the formatted equation is inserted in the Wordprocessor as a png bitmap. It needs a server which performs the conversion.
See homepage (external link) (Freeware, GPL)
Server installation files are available from the download page (external link).

Use a PowerPoint add-in

TexPoint enables the easy use of Latex symbols and formulas in Powerpoint presentations. See homepage (external link). (Shareware)
Latest version requires PowerPoint2000, does not work with earlier versions of PowerPoint.

Aurora (formerly named Ribbit) now also supports PowerPoint. See homepage (external link) (Shareware)

HTML as intermediate format


cost free unless otherwise stated

Because HTML is a structured format, the conversion between HTML and LaTeX is rather straightforward. However there remain the limitations of HTML compared to LaTeX, i.e. there are many elements in LaTeX which can not (yet?) be represented in HTML. Converters from LaTeX to HTML are:

Recommended if you have TeX installed or don’t mind to install it: TeX4ht (external link) is a highly configurable TeX-based converter to hypertext. It comes with a built-in default setting for plain TeX, LaTeX and TeXinfo, and it generates html with accompanying css stylesheet, xhtml, or xml. The converter needs a full TeX installation, but this gives the advantage that TeX’s full support for macros and styles is available (with only few exceptions).
Equations are converted to either bitmaps or MathML. There are some different MathML flavors around which can be chosen by an option. (Following description is partially copied from the TeX4ht web site.)
The special command
is available for producing xml compatible with OpenOffice (and probably also StarOffice). The output of the command oolatex <filename> is a zipped file with same name and a “.sxw” extension (containing the document in xml format which does not suffer the limitations of html). For this to work, TeX4ht needs a zip program which is not included in the TeX4ht distribution. It can e.g. be downloaded from (external link).
The resulting .sxw file can directly be opened in OpenOffice, converted equations are editable in OpenOffice’s own equation editor. OpenOffice can save the document also in MS Word 97/2000/XP format, but many equations are not correctly converted to Word. This is known to the OpenOffice developers for long, but yet not fixed.
A command of the form
htlatex filename "html,word" "symbol/!"
asks for HTML output tuned toward MicroSoft Word. Such a format, however, relies on bitmaps for mathematical formulas.
Conversion to bitmaps additionally needs Ghostscript and ImageMagic or netpbm.
For more information see (external link).

TTH (external link): LaTeX-to-HTML converter which translates LaTeX into HTML 4.0 markup. Formulae are also translated into standard html markup. (Free for non-commercial applications.)
A sister of tth, TtM (external link), converts formulae to MathML (Linux version for free, Windows version must be paid).

ltoh (external link): LaTeX-to-HTML converter which is highly customizable, i.e. you can define how the LaTeX macros which are used in your document are to be translated. Requires that the input file conforms to LaTeX2e (see documentation). It was last updated 1979, and it seems that the homepage is no longer available, so look on CTAN in …/support/ltoh/ .

HEVEA (external link): LaTeX-to-HTML converter which translates LaTeX into HTML4.0 markup. Formulae are also translated into standard html markup (not yet using MathML).

Hyperlatex (external link) allows the use of a subset of LaTeX to produce documents in HTML .

Some converters are available from CTAN (external link) (“Comprehensive TeX Archive Network”), e.g. in …/support/latex2html.
(The … stands for a host specific base directory, which often is either “/pub/tex” or “/tex-archive”)

HTML to Wordprocessor

Word 8 (97) and up contain the html converter by default (but its installation may have to be explicitly chosen during the Word setup in user-defined mode).
For Word 6 and 7 (95) for Windows and Mac there are free HTML converters available from Microsoft:
Download… IA for Word 6 (external link) / IA for Word 7 (95) (external link) / IA for Word for Mac (external link)

WordPerfect 7 and up have an integrated InternetPublisher.
For WordPerfect 6.1 for Windows, the InternetPublisher is available separately:
Download… InternetPublisher for WPWin 6.1 (external link)

OpenOffice can also import html, but much better is using tex4ht for lossless conversion to native OpenOffice format.

Other intermediate formats

There are ways to use SGML as intermediate format, and others have used it successfully. Having had a quick look at it, I found it rather complicated, especially it seems that you have to define the translation rules yourself. So I did not put more effort in trying to use it. If anyone can give me a ready-to-use cookbook solution, I will include it here.

An upcoming format is XML, a subset of which can be exported and imported by Microsoft Office 2000 and up, OpenOffice uses it as its native format, and the browser programmers are working on implementing XML. It actually is an instance of SGML. As it is more powerful than HTML, conversion from LaTeX to XML would lose much less information than conversion from LaTeX to HTML. There are good chances that it could be used as a general exchange format in the future. TeX4ht already has scripts for converting to XML (TEI or DOCBOOK). MS Word 2000 and earlier can not import XML, for these target systems convert to html+css using the xwtex and xwlatex scripts. MS Word 2003 can export and import XML, but I haven’t yet tested whether it can import the TEI or DOCBOOK files produced by TeX4ht.
The most successful path is using TeX4ht to convert to the OpenOffice format (.sxw, which actually is a zip compressed archive containing the document and vector graphics as XML and the bitmap graphics as bitmap files) and open this in OpenOffice. One could stop there, as OpenOffice is publicly available, or go on and save from OpenOffice as a “MS Word 97/2000/XP” file.

Most astonishing, one could also use PDF as intermediate format. Generating PDF from LaTeX is straightforward if you have a full TeX implementation installed. If you have the full commercial version of Adobe Acrobat 7, you can open the pdf and “save as” e.g. rtf (saving “as Word doc” actually generates an rtf file, too), xml, or plain text. Or you can use other commercial software to convert PDF to Word, just do a www search for “pdf to word” to get several hits. In this path of conversion however the document strucure and probably some formatting will be lost.

Finally, you can use OCR software to convert any printed document to word or plain text. To avoid the inaccuracy introduced by printing to paper and scanning, you can convert the TeX output to ps or pdf, convert this to a bitmap (using ghostscript), and feed this bitmap into the ocr software.

Convert to FrameMaker

la2mml: converts LaTeX to FrameMaker format. Maybe outdated, latest version was created Nov. 1995.
See more detailed page.
homepage (external link)

FrameMaker Utilities: Contains converters for both directions (LaTeX <-> FrameMaker) as well as templates which make conversion from Framemaker to LaTeX more easy
homepage (external link)

This HTML page is part of the texconv pages.
Copyright © 1998 … 2009 Wilfried Hennings
You may copy and redistribute it under the following conditions:

  • it must remain intact and the contents unchanged; if you’d like to have something changed, contact me (texconvfaq “at” Reformatting (e.g. from HTML to some other presentation format) is granted as long as the contents are unchanged.
  • you may NOT ask money for it except a reasonable cost for media and distribution

Please also note the disclaimer.

Calculation of Laminar Flow through Fracture

The calculation of laminar flow through fracture is very fundamental (), and it is very important for my research, also. Late last year, I derived the equation for both Newtonian fluid and non-Newtonian fluid by hand. Now I am going to make a note for that derivation for Newtonian fluid, which could be regarded as the answer to an exercise on Transport Phenomena, 2nd Ed. by Bird, R.B., et al., a classical textbook on this topic.

At first we need to describe the physical properties of the fracture model (as shown in Figure.1).

Figure 1. Physical Properties of Fracture Model

A Newtonian fluid is in laminar flow in a narrow slit formed by two parallel walls with length, L, a distance B (fracture width) apart. It is understood that the fracture height, B《W, so that “edge effects” are unimportant. Make a differential momentum balance, and obtain the following expressions for the momentum-flux and velocity distributions:

\tau_{yz}=\left ( \frac{p_{0}-p_{L}}{L}\right)x

v_{z}=\frac{\left (p_{0}-p_{L}\right)B^{2}}{2\mu L}\left [ 1-\left ( \frac{x}{B} \right )^{2} \right ]

Obtain the slit analog of the Hagen-Poiseuille equation.

w=\frac{1}{12} \frac{\left (p_{0}-p_{L}\right)B^{3}W\rho }{\mu L}

Superabsorbent Polymer

Note: In this post, I would like to introduce the superabsorbent polymer (SAP),which could be used as conformance control agent in oil and gas field. SAPs could absorb and hold a large amount of water or aqueous solutions even under high pressure and high temperature. Just as described in the summary of my proposal, in my research, I mainly test the flow properties of SAP through the fracture or fracture-like model, and the rheological properties with rheometer. Some of the swelling and deswelling behaviors and the effects on the injectivity of SAP through fractures were investigated also. Today SAPs will be introduced in general here. Later,  The following context is modified from an unpublished paper by my advisor and me. All rights reserved.

The superabsorbent polymers (SAPs) most commonly available are hard, dry, granular or powdered products made up of a cross-linked polymer with a three dimensional network structure that absorbs and holds a large amount of water and swells up to 200 times its original size and weight in fresh water or aqueous solutions while maintaining its physical structure. [1-4] SAPs are increasingly used in multiple fields of human activity, such as biomedical, agricultural, personal care, and industrial because of its high water absorbing capability. [4-6] Recently, SAPs have been applied in conformance control and water shutoff because they have significant advantages over the bulk gels used in in situ gelling processes, such as controllable size and strength, high chemical and temperature resistance, minimum formation damage, less surface facility requirements, and environmental friendly. [7] Except for the super water absorbency, the mechanical properties of SAPs are very important to the conformance control processes, such as the strength and injectivity. Dynamic mechanical analysis (DMA), rheometry and core flooding experiments are commonly used to determine the mechanical properties. Comparing to core flooding experiments, DMA and rheometry are much more cost-effective.

The SAP used in the research is LiquiBlock™ 40K (40K), a commercial product from Emerging Technology Inc. 40K is crosslinked acrylamide/potassium acrylate copolymer and the major component is 2-Propenoic acid, potassium salt, polymer with 2-proenamide. Its molecular structure is shown in Scheme 1.

Scheme 1. The molecular structure of 2-Propenoic acid, potassium salt, polymer with 2-proenamide.

In preparation for the rheological experiments, preselected dried SAP particles between 20- and 30-mesh were dispersed in 0.05%, 0.25%, 1.00%, and 10.00% sodium chloride solutions for 24 hours to achieve the maximum swelling. Because the density of both dried SAP and swollen SAP is higher than the density of brine, the swollen SAP always precipitated at the bottom of the centrifuge cell. The original and ultimate volumes of SAP in a centrifuge cell were recorded. The swelling ratio of the SAP was calculated from the following equation:

S_{w}=\frac{V_{s}}{V_{d}}\times 100\%

where Vs is the volume of swollen SAP and V0 is its original volume. Table 1 shows the ultimate swelling ratios for SAPs in various concentrations of brine.

Table 1. Swelling Ratios for SAP in Brine

Brine Conc.
Swelling Ratio
Original Dia.
Swollen Dia.
0.05 20455 0.595-0.841 3.506-4.955
0.25 9659 0.595-0.841 2.730-3.859
1.00 5682 0.595-0.841 2.287-3.233
10.00 3125 0.595-0.841 1.874-2.649


1. Tang, H. (ChemEOR, Inc.) U.S. USPTO 20,070,204,989

2. Bai, B.; Liu, Y.; Coste, J.-P.; Li, L. SPE Res Eval & Eng 2007, 10, 415-422.

3. Das, M.; Zhang, H.; Kumacheva, E. Annu. Rev. Mater. Res. 2006, 36, 117-144.

4. Buchholz, F. L.; Graham, A. T. In Modern Superabsorbent Polymer Technology; John, Wiley & Sons, Inc.: New York, 1997; chapter 1, 7, pp 22.

5. Raju, K. M.; Raju, M. P.; Mohan, Y. M. Polym. Int. 2003, 52, 768-772.

6. Samchenko, Y. M.; Ul’berg, Z. R.; Komarskii, S. A. Colloid J. 2004, 66, 350-354.

7. Liu, Y.; Bai, B.; Wang, Y. Oil Gas Sci. Technol. – Rev. IFP. 2010.