Add altmetric badges to paper (alshedivat#950)

[Altmetric](https://www.altmetric.com/) tracks social media and citation
activity for a paper. I added an option to add the altmeric id to a
paper's bib entry, which results in the altmeric badge for the paper
being displayed next to the other buttons. As an example, I added the
altmetric id for the Einstein, Podolsky & Rosen paper.

README.md

@@ -421,6 +421,7 @@ There are several custom bibtex keywords that you can use to affect how the entr
 - `poster`: Adds a "Poster" button redirecting to a specified file (if a full link is not specified, the file will be assumed to be placed in the /assets/pdf/ directory)
 - `slides`: Adds a "Slides" button redirecting to a specified file (if a full link is not specified, the file will be assumed to be placed in the /assets/pdf/ directory)
 - `website`: Adds a "Website" button redirecting to the specified link
+- `altmetric`: Adds an [Altmetric](https://www.altmetric.com/) badge (Note: only add the altmetric identifier here - the link is generated automatically)
 
 You can implement your own buttons by editing the bib.html file.
 

_bibliography/papers.bib

@@ -44,6 +44,7 @@ @article{howland_double-diffusive_2023
   abstract = {Motivated by the ablation of vertical ice faces in salt water, we use three-dimensional direct numerical simulations to investigate the heat and salt fluxes in two-scalar vertical convection. For parameters relevant to ice-ocean interfaces in the convection-dominated regime, we observe that the salinity field drives the convection and that heat is essentially transported as a passive scalar. By varying the diffusivity ratio of heat and salt (i.e., the Lewis number \(Le\)), we identify how the different molecular diffusivities affect the scalar fluxes through the system. Away from the walls, we find that the heat transport is determined by a turbulent Prandtl number of \(Pr_t \approx 1\)\ and that double-diffusive effects are practically negligible. However, the difference in molecular diffusivities plays an important role close to the boundaries. In the (unrealistic) case where salt diffused faster than heat, the ratio of salt-to-heat fluxes would scale as \(Le^\{1/3\}\), consistent with classical nested scalar boundary layers. However, in the realistic case of faster heat diffusion (relative to salt), we observe a transition towards a \(Le^\{1/2\}\)\ scaling of the ratio of the fluxes. This coincides with the thermal boundary layer width growing beyond the thickness of the viscous boundary layer. We find that this transition is not determined by a critical Lewis number, but rather by a critical Prandtl number \(Pr \approx 10\), slightly below that for cold seawater where \(Pr=14\). We compare our results to similar studies of sheared and double-diffusive flow under ice shelves, and discuss the implications for fluxes in large-scale ice-ocean models. By coupling our results to ice-ocean interface thermodynamics, we describe how the flux ratio impacts the interfacial salinity, and hence the strength of solutal convection and the ablation rate.},
   arxiv = {2207.09230},
   bibtex_show = {true},
+  altmetric = {140833627},
   selected = {true},
   preview = {DDVC_3D.png}
 }

_config.yml

@@ -254,7 +254,7 @@ scholar:
   query: "@*"
 
 # Filter out certain bibtex entry keywords used internally from the bib output
-filtered_bibtex_keywords: [abbr, abstract, arxiv, bibtex_show, html, pdf, selected, supp, blog, code, poster, slides, website, preview]
+filtered_bibtex_keywords: [abbr, abstract, arxiv, bibtex_show, html, pdf, selected, supp, blog, code, poster, slides, website, preview, altmetric]
 
 # Maximum number of authors to be shown for each publication (more authors are visible on click)
 max_author_limit: 3  # leave blank to always show all authors

_layouts/bib.html

@@ -180,6 +180,9 @@
           {%- if entry.doi %}
             <a href="https://doi.org/{{ entry.doi }}" class="btn btn-sm z-depth-0" role="button">Journal</a>
           {%- endif %}
+          {%- if entry.altmetric %}
+            <script type="text/javascript" src="https://d1bxh8uas1mnw7.cloudfront.net/assets/embed.js"></script><div data-altmetric-id="{{ entry.altmetric }}" class="altmetric-embed" data-hide-no-mentions="true" data-hide-less-than="15" data-badge-popover="right" data-badge-type="2" style="display:inline"></div>
+          {%- endif %}
           </div>
 
           {% if entry.abstract -%}