The method can further include using in a computer the characterized chemical composition of the given crude oil to predict physical and chemical properties of the given crude oil. In another embodiment, a method of blending crude oil includes, for each of two or more crude oil samples to form a blend, characterizing each of the crude oil samples by chemical composition and predicted physical and chemical properties, said characterizing resulting in respective characterizations of the two or more crude oil samples.
The method further includes, based on said characterizations, determining respective ratios of the two or more crude oil samples, such that a resulting blend using the respective ratios of the sample crude oils has certain chemical composition and predicted physical and chemical properties, and forming the blend using amounts of the two or more sample crude oils in the determined respective ratios.
The steps of characterizing each of the crude oil samples are as described above. This invention has many advantages, including a scientific i. The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views.
The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention. Also included are asphaltene molecules represented as condensed aromatic molecules with 7 aromatic or cyclohexane rings and 6 n-alkyl side chains with up to 9 zero-branch methylene groups. Also shown are boiling point curves as a function of carbon number for n-paraffins FIG. Also shown are density curves as a function of carbon number for n-paraffins FIG.
Also shown are viscosity curves as a function of carbon number for n-paraffins FIG. A description of example embodiments of the invention follows. Molecular Characterization of Petroleum Fractions. See Watt; M. Klein, G. Hou, R. Bertolacini, L. Broadbelt, A. See R.
Quann, S. Jaffe, H. Freund, W. Individual hydrocarbon molecules are represented by this model as vectors of incremental structural features that can describe the composition, reactions, and properties of petroleum mixtures. Chemical compositions of the individual hydrocarbon molecules are inferred from analytical measurement results.
See E. Eckert, T. The Molecularly Explicit Characterization Model MECM of Albahri uses routinely made measurements of a petroleum fraction's bulk properties such as the ASTM D86 distillation, API gravity, Reid vapor pressure, and the paraffin, naphthene, and aromatic content along with the pure components' properties to define chemical compositions of petroleum fuels suitable for simulation purposes.
While Albahri demonstrated that the complex nature of petroleum fuels can be modeled by a limited set of representative pure components, the number and type of components chosen to represent a petroleum fraction, a key factor in determining the accuracy of the representation, is difficult to determine. See Y. Wu, N. Same Aye, N. Recently, in support of kinetic model development for petroleum conversion processes, Pyl et al.
See S. Pyl, Z. Hou, K. Van Geem, M. Reyniers, G. Marin, M. A homologous series has a particular core structure, but has a variable aliphatic side chain length or a variable number of aliphatic side chains. The carbon number in each homologous series varies from a minimal carbon number C min to a maximum carbon number C max , by varying the side chain length of the homologous series core structure.
In the present invention, a molecule-based approach characterizes crude oil and petroleum fractions for correlation, prediction, and estimation of assays and properties of crude oil, crude oil blends, petroleum fractions, and petroleum mixtures without using user-defined core structures, and without using structural lumping which requires large amounts of analytical data.
The present invention approach employs a systematic methodology that determines numbers and types of molecules and their compositions to broadly represent physical and chemical properties of crude oil and petroleum fractions by constructing candidate compositions based on particular cross sections of segment type and segment number range and corresponding probability distribution functions.
It is well recognized that hydrocarbon molecules in crude oil are mainly composed of three classes of hydrocarbon molecules: paraffinic P , naphthenic N , and aromatic A. The paraffins include saturated hydrocarbons with linear chains, i. The naphthenes are saturated hydrocarbons with one or more naphthenic rings plus paraffinic side chains.
The paraffins and the naphthenes together are called the saturates. The aromatics are hydrocarbons with aromatic rings, naphthenic rings, and paraffinic side chains. Additionally, sulfur, nitrogen, and oxygen may also be present as hetero-atoms with these hydrocarbon molecules and form various sub-classes such as thiophenes, carbozoles, phenols, naphthenic acids, etc.
In the present invention, crude oil and petroleum fractions are similarly defined as mixtures of selected classes of hydrocarbon constituent molecules, i. For each of the selected classes and sub-classes of hydrocarbon constituent molecules, their probability distribution functions are determined and optimized as described below. The use of probability distribution functions for classes and sub-classes of hydrocarbon constituent molecules in the present invention is less burdensome than traditional methods in terms of the amount of experimental data needed for computations of physical properties of crude oil, and enables easier adjustment of the profile i.
Physical properties of selected classes of hydrocarbon constituent molecules for crude oil and petroleum fractions can be estimated with the segment-based PC-SAFT equation of state that enables rigor, accuracy, and thermodynamic consistency in the calculation of fundamental physical properties such as vapor pressure, boiling point, density, and heat capacity.
See J. Gross, G. Gross, O, Spuhl, F. Tumakaka, G. Missing properties of the crude oil assay are then estimated from the chemical compositions and the properties of these hydrocarbon constituent molecules.
Utilities of this approach are further validated with the extensive crude oil assays available in the public domain. To refine the molecular characterization for additional critical assay measurements, additional classes or subclasses of hydrocarbon constituent molecules can be optionally introduced on top of the three main classes of hydrocarbon constituent molecules, i.
This molecule-based approach offers a much stronger scientific i. The central premise of the molecule-based approach described herein is that 1 proper selection of classes and sub-classes of model hydrocarbon constituent molecules and practical rules for automatically generating and constructing these model molecules from structural segments for crude oil, 2 recent advances in molecular thermodynamic models that facilitate accurate and thermodynamically consistent physical property calculations for hydrocarbon constituent molecules, and 3 robust algorithm for identification of chemical compositions for model hydrocarbon constituent molecules from regression of assay experimental data.
Together they form a comprehensive and practical molecular characterization approach to correlate and estimate physical and chemical properties of crude oil and petroleum fractions. Successful implementation of such a molecular characterization approach offers a highly sought-after molecular insight into complex petroleum mixtures for optimal utilization and processing of such valuable natural resources.
In addition, it generates a consistent set of model hydrocarbon constituent molecules and their chemical compositions for planning, scheduling, process simulation, design, optimization, and control of petroleum refining operations.
As the carbon number increases, the numbers of possible hydrocarbon constituent molecules in crude oil increase exponentially and they quickly become totally unmanageable.
See Saine Aye and Zhang. To minimize the number of model hydrocarbon constituent molecules required to fully characterize physical and chemical properties for crude oil and petroleum fractions, the instant application starts with the knowledge that crude oil in general is mainly composed of three different classes of hydrocarbon molecules: paraffins P , naphthenes N , and aromatics A.
In other words, crude oil and petroleum mixtures can be defined alike in terms of combinations of three classes of hydrocarbon constituent molecules, i. As an illustration, FIG. Here, the —CH 3 segment is the methyl end group, the —CH 2 — segment is the zero-branch methylene repeat group, the.
To show the broad ranges of physical properties represented by these hydrocarbon constituent molecules, the corresponding boiling points, densities, and viscosities of these components are shown in FIGS. The boiling points and densities are estimated with the segment-based PC-SAFT equation-of-state EOS , while the viscosities are estimated by employing group contribution methodology. See Gross ; Gross ; B. Poling, J. Prausnitz, J. Sulfur molecules such as mercaptans, sulfides, and thiophenes can be present in crude oil in significant amounts.
Nitrogen molecules such as carbozoles and quinolones, oxygen molecules such as phenols and naphthenic acids, and asphaltene molecules can also be present in certain crude oil.
Additional classes or subclasses of hydrocarbon constituent molecules and corresponding structural segments may be added in addition to the P, N, and A molecules and their structural segments in order to provide sufficient fidelity for crude oil properties and assays.
In one illustrative embodiment, each molecule is considered, as discussed above, as one of three classes of hydrocarbon constituent molecules, i.
For example, n-paraffin P molecules are considered as molecules made up of four types of segments: —CH 3 , —CH 2 —, —CH—, and —C—, wherein the number of —CH 3 segments is always two, the number of —CH— segments is always zero, and the number of —C—segments is always zero in order to construct realistic n-paraffin P molecules from these four types of segments.
Certain constraints are imposed to construct realistic molecules from these four types of segments. Specifically, the number of —CH 3 segments is not an independent variable, because it is dependent on the numbers of the other three types of segments. For an iso-paraffin P molecule with l —CH 2 — segments, m —CH— segments, and n —C— segments, the component mole fraction y l,m,n p is defined as the product of four quantities: 1 the class P molecule mole fraction y p class , 2 the —CH 2 — segment number probability p p —CH2— l for class P molecules, 3 the —CH— segment number probability p p —CH— m for class P molecules, and 4 the —C— segment number probability p p —C— n for class P molecules.
To identify compositions of the selected molecules, probability distribution functions and associated parameters for the structural segments for each class of molecules, i. A variety of probability distribution functions can be considered. For example, a gamma distribution function is a two parameter family of probability distributions of the form.
The relative contents of the three classes of hydrocarbon constituent molecules are then identified from regression against assay physical and chemical data such as true boiling point, API gravity, viscosity, paraffin content, naphthene content, and aromatic content of selected distilled fractions as described below. The segment-based PC-SAFT equation-of-state EOS is used to develop a thermodynamically consistent framework to accurately calculate physical properties for the model hydrocarbon constituent molecules and their mixtures.
See Gross ; Gross See Gross These parameters are identified from regression of experimental data on vapor pressure, liquid density and liquid heat capacity of hundreds of hydrocarbon compounds made up of these segments. These segment parameters together with the PC-SAFT EOS provide a rigorous and predictive thermodynamic framework based on principles of statistical mechanics This thermodynamic framework enables systematic exploration of different classes of molecules with various types of segments and segment number ranges.
In contrast, typical cubic equations of state such as Peng-Robinson and Redlich-Kwong-Soave are only capable of calculating vapor pressure accurately. These cubic equations of state are incapable of calculating liquid density accurately. For paraffins, C 1 and C 2 are identified to be For naphathenes and aromatics, C 1 and C 2 are identified to be Identifying Molecular Distribution Parameters.
To illustrate by an example of a specific crude oil, FIGS. These experimental assay data are regressed simultaneously to identify the hydrocarbon constituent molecule segment probability distribution function parameters, including the relative P, N, and A contents and the probability distribution function parameters for the structural segments for each class of molecules. Additional experimental assay data can also be included in the regression. In this specific example, the probability distribution functions and associated parameters for the structural segments and the P, N, and A contents are simultaneously adjusted in the regression to fit the true boiling point data, the API gravity data, and the viscosity data.
The optimized values of these P, N, and A contents and the associated segment probability distribution functions and function parameters for the UK Brent crude the Forties blend are given in Table 4.
Note that the interaction parameter k 0 for the mixture viscosity correlation see Eq. In practice, depending on the nature of the available experimental assay data, the P, N, and A contents and the probability distribution function parameters can be sequentially or simultaneously adjusted in the regression to provide an optimal fit to the experimental assay data.
The probabilities are based on the gamma distribution function parameters reported in Table 4. The same methodology described above for identifying the molecular distribution parameters can be applied directly to petroleum fractions which have limited boiling point ranges.
Conversely, if data are available for these physical and chemical properties, they can be used in the regression methodology described above to identify optimal molecular distribution parameters. The molecular distribution parameters for crude oil further provide the molecular basis for crude oil blending calculations. Traditionally, an arbitrary set of pseudocomponents is applied to all crude oil to be blended, and crude blending is then performed on the pseudocomponent level.
In contrast, no such pseudocomponents are required for crude blending with the molecule-based approach. There is also dvilualatex to produce a. XeTeX produces a. Internally, XeTeX creates an. These commands provide significant additional support for Japanese and other languages; the u variant supports Unicode. These are candidates for an upcoming LaTeX release. The main purpose is to find and address compatibility problems before an official release. These -dev formats make it easy for anyone to help test documents and code: you can run, say, pdflatex-dev instead of pdflatex , without changing anything else in your environment.
Indeed, it is easiest and most helpful to always run the -dev versions instead of bothering to switch back and forth. During quiet times after a release, the commands will be equivalent. These are not daily snapshots or untested development code.
They undergo the same extensive regression testing by the LaTeX team before being released. The name itself then consists of either a a string of letters or b a single non-letter. Most command names are lowercase, but in any event you must enter all commands in the same case as they are defined. A command may be followed by zero, one, or more arguments. These arguments may be either required or optional.
Optional arguments are contained in square brackets, [ Generally, but not universally, if the command accepts an optional argument, it comes first, before any required arguments. Similarly, if an optional argument comes last, with no required argument after it, then to make the first character of the following text be an open square bracket, hide it inside curly braces.
The exact difference in behavior varies from command to command. They provide a completely different underlying programming language syntax. An environment is an area of LaTeX source, inside of which there is a distinct behavior. See Environments , for a list of environments. The environment-name at the beginning must exactly match that at the end. Environments may have arguments, including optional arguments.
This example produces a table. The first argument is optional and causes the table to be aligned on its top row while the second argument is required it specifies the formatting of columns. It is a set of Internet sites around the world that offer material related to LaTeX for download.
This material is organized into packages, discrete bundles that typically offer some coherent functionality and are maintained by one person or a small number of people. In addition to the massive holdings, the ctan. The master host actively manages the material, for instance, by accepting uploads of new or updated packages.
Other sites around the world help out by mirroring, that is, automatically syncing their collections with the master site and then in turn making their copies publicly available. This gives users close to their location better access and relieves the load on the master site. The following document class names are built into LaTeX.
Many other document classes are available as separate packages; see Overview. For documents of length between an article and a book , such as technical reports or theses, which may contain several chapters. For slide presentations—rarely used nowadays. See beamer template , for a small template for a beamer document.
To specify more than one option , separate them with a comma. All of the standard classes except slides accept the following options for selecting the typeface size default is 10pt :. All of the standard classes accept these options for selecting the paper size these show height by width :. The geometry package provides flexible ways of setting the print area and physical page size.
Mark draft or do not mark final overfull boxes with a black box in the margin; default is final. Specifies whether there is a separate page for the title information and for the abstract also, if there is one.
The default for the report class is titlepage , for the other classes it is notitlepage. Selects one- or two-sided layout; default is oneside , except that in the book class the default is twoside.
For one-sided printing, the text is centered on the page. Determines if a chapter should start on a right-hand page; default is openright for book , and openany for report. The slides class offers the option clock for printing the time at the bottom of each note. Load a package pkg , with the package options given in the comma-separated list options , as here. You can create new document classes and new packages. For instance, if your memos must satisfy some local requirements, such as a standard header for each page, then you could create a new class smcmemo.
What separates a package from a document class is that the commands in a package are useful across classes while those in a document class are specific to that class. Thus, a command to set page headers is for a package while a command to make the page headers say Memo from the SMC Math Department is for a class. This allow you to create commands that users will not accidentally redefine.
Another technique is to preface class- or package-specific commands with some string to prevent your class or package from interfering with others. Here is a starting class file, which should be saved as stub. Save in a box register things that are written to the. Hook to insert code to be executed when LaTeX finishes processing the current class or package. You can use these hooks multiple times; the code will be executed in the order that you called it.
Raises an error when the check fails. This allows you to check before you start redefining cmd yourself that no other package has already redefined this command. If the user then asks for help by typing h , they see the help text. The four warning commands are similar except that they write warning text on the screen with no error prompt.
The four info commands write info text only in the transcript file. The NoLine versions do not show the number of the line generating the message, while the other versions do show that number. Note that LaTeX appends a period to the messages. Expands to the name of the currently-being-processed option.
If you request an option that has not been declared, by default this will produce a warning like Unused global option s : [badoption].
Another example is that the class smcmemo may allow users to keep lists of memo recipients in external files.
This code handles the file if it exists and otherwise passes the option to the article class. Use this command to define new robust commands or to redefine existing commands and make them robust. Execute true code if LaTeX finds the file file name or false code otherwise.
In the first case it executing true code and then inputs the file. Thus the command. This command looks for the file in all search paths that LaTeX uses, not only in the current directory. If you ask for a filename without a. The options list , if present, is a comma-separated list. The release date is optional. If you request a release date and the date of the package installed on your system is earlier, then you get a warning on the screen and in the log like this.
This is a convenience command that lets you build classes on existing ones, such as the standard article class, without having to track which options were passed.
If this command is not defined then that option is silently ignored. Specifies the format that this class must be run under. When a document using that class is processed, the format name given here must match the format that is actually being run including that the format string is case sensitive.
To specify a version of the format that you know to have certain features, include the optional format date on which those features were implemented. If the format version installed on your system is earlier than format date then you get a warning like this.
Adds the current option to the list of unused options. The reason for these commands is: you may load a package any number of times with no options but if you want options then you may only supply them when you first load the package.
Loading a package with options more than once will get you an error like Option clash for package foo. LaTeX throws an error even if there is no conflict between the options. However, imagine that you are loading firstpkg and inside that package it loads secondpkg , and you need the second package to be loaded with option draft. Then before doing the first package you must queue up the options for the second package, like this.
If firstpkg. These commands are useful for general users as well as class and package writers. For instance, suppose a user wants to load the graphicx package with the option draft and also wants to use a class foo that loads the graphicx package, but without that option.
Execute the code for each option that the user has invoked. Options come in two types. For a package this means that the global options are processed first. If the name of the file does not match the class or package name declared in it then you get a warning. This warning does not prevent LaTeX from processing the rest of the class file normally.
The rest of the optional argument is free-form, although it traditionally identifies the class, and is written to the screen during compilation and to the log file. Thus, if your file smcmemo. The date in the optional argument allows class and package users to ask to be warned if the version of the class or package is earlier than release date. Although, in practice package users only rarely include a date, and class users almost never do. Declare a file other than the main class and package files, such as configuration files or font definition files.
Put this command in that file and you get in the log a string like File: test. The option list , if present, is a comma-separated list. This is a convenience command to allow easily building classes on existing ones without having to track which options were passed. LaTeX comes with powerful font capacities. For one thing, its New Font Selection Scheme allows you to work easily with the font families in your document for instance, see Font styles.
Note, though, that many fonts do not have support for mathematics. It is the default for LaTeX documents and is still the most widely used. But changing to another font often only involves a few commands. For instance, putting the following in your preamble gives you a Palatino-like font, which is handsome and more readable online than many other fonts, while still allowing you to typeset mathematics.
In addition, the xelatex or lualatex engines allow you to use any fonts on your system that are in OpenType or TrueType format see TeX engines. It aims to cover all Latin alphabet free fonts available for easy use with LaTeX.
Specify the font encodings. A font encoding is a mapping of the character codes to the font glyphs that are used to typeset your output. This package only applies if you use the pdflatex engine see TeX engines. If you use the xelatex or lualatex engine then instead use the fontspec package. TeX users have agreed on a number of standards to access the larger sets of characters provided by modern fonts. If you are using pdflatex then this in the preamble.
In particular, if you have words with accented letters then LaTeX will hyphenate them and your output can be copied and pasted. The optional second line allows you to directly enter accented characters into your source file. If you are using an encoding such as T1 and the characters appear blurry or do not magnify well then your fonts may be bitmapped, sometimes called raster or Type 3.
You want vector fonts. TeX text extended. Sometimes called the Cork encoding for the Users Group meeting where it was developed. Gives access to most European accented characters. The most common option for this package.
Even if you do not use accented letters, you may need to specify a font encoding if your font requires it. If you use T1 encoded fonts other than the default Computer Modern family then you may need to load the package that selects your fonts before loading fontenc , to prevent the system from loading any T1 encoded fonts from the default. This package provides a number of commands, detailed below. Many of them are encoding-specific, so if you have defined a command that works for one encoding but the current encoding is different then the command is not in effect.
Declare the font encoding encoding. The math-settings are the commands that LaTeX will use whenever the font is accessed as a math alphabet. LaTeX ignores any space characters inside text-settings and math-settings , to prevent unintended spaces in the output. Note that output encoding files may be read several times by LaTeX so using, e.
Default commands only in a package, not in the encoding definition files, since those files should only contain declarations specific to that encoding. Define an accent, to be put on top of other glyphs, in the encoding encoding at the location slot. This line from t1enc. Define the command cmd , which will be specific to one encoding. These commands can only appear in the preamble. Redefining cmd does not cause an error. Briefly, nargs is an integer from 0 to 9 specifying the number of arguments that the defined command cmd takes.
This number includes any optional argument. Omitting this argument is the same as specifying 0, meaning that cmd will have no arguments. Give a default definition for cmd , for when that command is not defined in the encoding currently in force. This default should only use encodings known to be available. It should instead be in a package. So, packages can use it to provide fallbacks that other packages can improve upon.
Access an accented glyph directly, that is, without having to put an accent over a separate character. See fontenc package , for a list of common encodings.
The slot argument is usually a positive integer represented in decimal although octal or hexadecimal are possible. In t1enc. Define a symbol in the encoding encoding at the location slot. Symbols defined in this way are for use in text, not mathematics. For example, this line from t1enc.
The slot can be specified in decimal, or octal as in ' , or hexadecimal as in "13 , although decimal has the advantage that single quote or double quote could be redefined by another package. Get the name of the most recently declared encoding. In general, to use a fontenc command in an encoding where it is not defined, and if the command has no arguments, then you can use it like this:.
Similarly, to use a fontenc command in an encoding where it is not defined, and if the command has one argument, you can use it like this:. This is the preferred form. But shown after it in parenthesis is the corresponding declaration form , which is often useful. The scope of the declaration form lasts until the next type style command or the end of the current group. LaTeX also provides the following commands, which unconditionally switch to the given style, that is, are not cumulative.
The unconditional commands below are an older version of font switching. The earlier commands are an improvement in most circumstances. But sometimes an unconditional font switch is what is needed. The following commands are for use in math mode.
This is because typically math symbols need consistent typographic treatment, regardless of the surrounding environment.
Many other fonts have old-style numerals also; sometimes package options are provided to make them the default. The following standard type size commands are supported by LaTeX. The commands are listed here in declaration not environment form, since that is how they are typically used. For example. But in almost all cases, it would only cause confusion to use it.
The reason for mentioning the environment form of the font size declarations specifically is that this particular use is not rare. These commands are primarily intended for writers of macros and packages. The commands listed here are only a subset of the available ones. Select the font encoding, the encoding of the output font. There are a large number of valid encodings. Select the font family. Here are examples of some common families.
Select the font series. A series combines a weight and a width. Typically, a font supports only a few of the possible combinations. Some common combined series values include:. The possible values for width, individually, are the meaning and relationship of these terms varies with individual typefaces :.
The two last shapes are not available for most font families, and small caps are often missing as well. Set the font size and the line spacing. The unit of both parameters defaults to points pt. The line spacing is the nominal vertical space between lines, baseline to baseline. Best specified in the preamble, or use the setspace package, as just described. For example:. Start a new page and produce single-column output. If the document is given the class option onecolumn then this is the default behavior see Document class options.
Start a new page and produce two-column output. If the document is given the class option twocolumn then this is the default see Document class options.
If the optional prelim one column text argument is present, it is typeset in one-column mode before the two-column typesetting starts. The distance between columns. The default is 35pt. You must change it before the two column mode starts; in the preamble is a good place. The width of the rule between columns.
The default is 0pt, meaning that there is no rule. Otherwise, the rule appears halfway between the two columns. The width of a single column. LaTeX places starred floats at the top of a page.
The following parameters control float behavior of two-column output. The maximum fraction at the top of a two-column page that may be occupied by two-column wide floats. The default is 0. If the height of your starred float environment exceeds this then you can take one of the following actions to prevent it from floating all the way to the back of the document:.
For a float page of two-column wide floats, this is the minimum fraction that must be occupied by floats, limiting the amount of blank space.
On a float page of two-column wide floats, this length is the distance between floats, at both the top and bottom of the page.
The default is 12pt plus2pt minus2pt for a document set at 10pt or 11pt , and 14pt plus2pt minus4pt for a document set at 12pt. This length is the distance between a multi-column float at the top or bottom of a page and the main text. The default is 20pt plus2pt minus4pt. On a float page of two-column wide floats, this counter gives the maximum number of floats allowed at the top of the page. The LaTeX default is 2. Make all pages in the documents after this declaration have the same height, by stretching the vertical space where necessary to fill out the page.
This is most often used when making two-sided documents since the differences in facing pages can be glaring. Make all later pages the natural height of the material on that page; no rubber vertical lengths will be stretched. Thus, in a two-sided document the facing pages may be different heights. This command can go at any point in the document body. This is the default unless you select the twoside document class option see Document class options. The distance between the two columns, the width of a rule between the columns, and the width of the columns, when the document class option twocolumn is in effect see Document class options.
Height of the box that contains the running head. Vertical distance between the bottom of the header line and the top of the main text. Distance from the baseline of the last line of text to the baseline of the page footer. Width of the current line, decreased for each nested list see list. The minimum vertical space between two marginal notes, the horizontal space between the text body and the marginal notes, and the horizontal width of the notes.
The height of the paper, as distinct from the height of the print area. The width of the paper, as distinct from the width of the print area. The normal vertical height of the page body.
The full horizontal width of the entire page body. It should not be used in normal LaTeX documents. Space between the top of the TeX page one inch from the top of the paper, by default and the top of the header. Minimum distance between the top of the page body and the baseline of the first line of text. For the standard classes, the default is the same as the font size, e. It gives the leading, the normal distance between lines in a paragraph, from baseline to baseline. Nor does it mean that if the lines are spaced less than 12pt apart then they risk touching.
Rather these numbers are typographic judgements. So if a document contains this paragraph then its lines will be scrunched together, compared to lines in surrounding paragraphs.
There are two fine points. By the prior paragraph then, the distance between lines can approach zero but if it becomes zero or less than zero then the lines jump to 1pt apart. Sometimes authors must, for editing purposes, put the document in double space or one-and-a-half space. For double spacing, take factor to be 1. In the preamble these will start the document off with that sizing. Some typographic elements, such as figures and tables, cannot be broken across pages. They must be typeset outside of the normal flow of text, for instance floating to the top of a later page.
LaTeX can have a number of different classes of floating material. The default is the two classes, figure see figure and table see table , but you can create a new class with the package float. Within any one float class LaTeX always respects the order, so that the first figure in a document source must be typeset before the second figure. However, LaTeX may mix the classes, so it can happen that while the first table appears in the source before the first figure, it appears in the output after it.
The placement of floats is subject to parameters, given below, that limit the number of floats that can appear at the top of a page, and the bottom, etc. If so many floats are queued that the limits prevent them all from fitting on a page then LaTeX places what it can and defers the rest to the next page. In this way, floats may end up being typeset far from their place in the source. In particular, a float that is big may migrate to the end of the document.
In which event, because all floats in a class must appear in sequential order, every following float in that class also appears at the end.
In addition to changing the parameters, for each float you can tweak where the float placement algorithm tries to place it by using its placement argument.
The possible values are a sequence of the letters below. The default for both figure and table , in both article and book classes, is tbp. Bottom —at the bottom of a text page. Here —at the position in the text where the figure environment appears.
However, h is not allowed by itself; t is automatically added. Page of floats —on a separate float page , which is a page containing no text, only floats. Used in addition to one of the above; for this float only, LaTeX ignores the restrictions on both the number of floats that can appear and the relative amounts of float and non-float text on the page.
Note: the order in which letters appear in the placement argument does not change the order in which LaTeX tries to place the float; for instance, btp has the same effect as tbp. All that placement does is that if a letter is not present then the algorithm does not try that location.
This will wait until the current page is finished and then flush all outstanding floats. LaTeX can typeset a float before where it appears in the source although on the same output page if there is a t specifier in the placement parameter. Minimum fraction of a page that must be text; if floats take up too much space to preserve this much text, floats will be moved to a different page. Structure your text into divisions: parts, chapters, sections, etc.
All sectioning commands have the same form, one of:. The table has each sectioning-command in LaTeX. An example of using this is for an appendix in an article.
The section title title provides the heading in the main text, but it may also appear in the table of contents and in the running head or foot see Page styles. You may not want the same text in these places as in the main text. All of these commands have an optional argument toc-title for these other places. The level number in the table above determines which sectional units are numbered, and which appear in the table of contents.
LaTeX lets you change the appearance of the sectional units. CTAN has many packages that make this adjustment easier, notably titlesec. Controls which sectioning unit are numbered. See the above table for the level numbers. Controls which sectioning units are listed in the table of contents.
For instance, if tocdepth is 1 then the table of contents will list sections but not subsections. Start a document part. The standard LaTeX classes book , report , and article , all have this command. Then LaTeX outputs title , also alone on its line, in bold and in even larger type. In class book , the LaTeX default puts each part alone on its own page. If the book is two-sided then LaTeX will skip a page if needed to have the new part on an odd-numbered page. In an article LaTeX does not put it on a fresh page, but instead outputs the part number and part title onto the main document page.
The optional argument toc-title will appear as the part title in the table of contents see Table of contents etc. If it is not present then title will be there. This example puts a line break in title but leaves out the break in the table of contents. In the class article , if a paragraph immediately follows the part title then it is not indented. To get an indent you can use the package indentfirst. See its documentation on CTAN. Start a chapter. The standard LaTeX classes book and report have this command but article does not.
The LaTeX default starts each chapter on a fresh page, an odd-numbered page if the document is two-sided. It also increments the chapter counter, adds an entry to the table of contents see Table of contents etc. But it does not show the chapter number, does not increment the chapter counter, produces no table of contents entry, and does not affect the running header.
If you use the page style headings in a two-sided document then the header will be from the prior chapter. This example illustrates. The optional argument toc-title will appear as the chapter title in the table of contents see Table of contents etc.
This shows the full name in the chapter title,. The paragraph that follows the chapter title is not indented, as is a standard typographical practice. To get an indent use the package indentfirst. You can change what is shown for the chapter number. To make this change because of the primary language for the document, see the package babel. In a two-sided document LaTeX puts a chapter on odd-numbered page, if necessary leaving an even-numbered page that is blank except for any running headers.
But there are also many packages on CTAN that address this. One is titlesec. See its documentation, but the example below gives a sense of what it can do.
Start a section. The standard LaTeX classes article , book , and report all have this command. But it does not show the section number, does not increment the section counter, produces no table of contents entry, and does not affect the running header. If you use the page style headings in a two-sided document then the header will be from the prior section.
The optional argument toc-title will appear as the section title in the table of contents see Table of contents etc. This shows the full name in the title of the section,. This has a line break in title but that does not work with headers so it is omitted from the contents and headers. The paragraph that follows the section title is not indented, as is a standard typographical practice. One way to get an indent is to use the package indentfirst. There are also many packages on CTAN that address this, including titlesec.
See the documentation but the example below gives a sense of what they can do. Start a subsection. But it does not show the subsection number, does not increment the subsection counter, and produces no table of contents entry.
The optional argument toc-title will appear as the subsection title in the table of contents see Table of contents etc. This shows the full text in the title of the subsection,. The paragraph that follows the subsection title is not indented, as is a standard typographical practice. Start a subsubsection, paragraph, or subparagraph. The standard LaTeX classes article , book , and report all have these commands, although they are not commonly used.
The default output of each of the three does not change over the standard LaTeX classes article , book , and report. The other two divisions are not numbered. Learn More. Close Privacy Overview This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website.
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