Recreate a chapter style

Question

How can I recreate this particular style for both chapters and sections?

Answer 1

The code below will at least get you close, but you should investigate the titlesec package's documentation for more details, or consult the capabilities of your document class.

\documentclass{book}
\usepackage[T1]{fontenc}
\usepackage{newtxtext,newtxmath}% font like picture
\usepackage{titlesec}
% style chapters
\titleformat{\chapter}% sectioning command to format
    [block]% shape of chapter titles = number next to title
    {}% common formatting to number and title
    {{\fontsize{40}{40}\selectfont\bfseries\thechapter}% scaled bold chapter number
        \hspace{0.7em}\rule[2pt]{1.3pt}{6\baselineskip}}% vertical line
    {0.7em}% space between number and title
    {\Large\MakeUppercase}% style applied to title
% (use  after \titlespacing to unindent next paragraph)
\titlespacing{\chapter}% set spacing for chapter titles
    {0pt}% no space to left
    {0pt}% no space to above
    {\baselineskip}% skip one line afterwards
% style sections
\titleformat{\section}% sectioning command to format
    [block]% shape: number then title
    {\bfseries}% make both number and title bold
    {\thesection.}% number followed by period
    {0.5em}% space between number and title
    {\MakeUppercase}% style of title
\titlespacing{\section}% set spacing for section titles
    {0pt}% no space to left
    {1.4\baselineskip}% space above
    {0.6\baselineskip}% space below
\begin{document}
\chapter{General Thermodynamic Properties}
Text here.
\section{Extensive and Intensive Properties}
More text here.
\end{document}