---
_id: '10584'
abstract:
- lang: eng
  text: Electrically tunable lenses (ETLs) are those with the ability to alter their
    optical power in response to an electric signal. This feature allows such systems
    to not only image the areas of interest but also obtain spatial depth perception
    (depth of field, DOF). The aim of the present study was to develop an ETL-based
    imaging system for quantitative surface analysis. Firstly, the system was calibrated
    to achieve high depth resolution, warranting the accurate measurement of the depth
    and to account for and correct any influences from external factors on the ETL.
    This was completed using the Tenengrad operator which effectively identified the
    plane of best focus as demonstrated by the linear relationship between the control
    current applied to the ETL and the height at which the optical system focuses.
    The system was then employed to measure amplitude, spatial, hybrid, and volume
    surface texture parameters of a model material (pharmaceutical dosage form) which
    were validated against the parameters obtained using a previously validated surface
    texture analysis technique, optical profilometry. There were no statistically
    significant differences between the surface texture parameters measured by the
    techniques, highlighting the potential application of ETL-based imaging systems
    as an easily adaptable and low-cost alternative surface texture analysis technique
    to conventional microscopy techniques
acknowledgement: The authors acknowledge the financial assistance provided by the
  University of Huddersfield.
article_number: '17'
article_processing_charge: Yes
article_type: original
author:
- first_name: Jorabar Singh
  full_name: Nirwan, Jorabar Singh
  last_name: Nirwan
- first_name: Shan
  full_name: Lou, Shan
  last_name: Lou
- first_name: Saqib
  full_name: Hussain, Saqib
  last_name: Hussain
- first_name: Muhammad
  full_name: Nauman, Muhammad
  id: 32c21954-2022-11eb-9d5f-af9f93c24e71
  last_name: Nauman
  orcid: 0000-0002-2111-4846
- first_name: Tariq
  full_name: Hussain, Tariq
  last_name: Hussain
- first_name: Barbara R.
  full_name: Conway, Barbara R.
  last_name: Conway
- first_name: Muhammad Usman
  full_name: Ghori, Muhammad Usman
  last_name: Ghori
citation:
  ama: Nirwan JS, Lou S, Hussain S, et al. Electrically tunable lens (ETL) - based
    variable focus imaging system for parametric surface texture analysis of materials.
    <i>Micromachines</i>. 2022;13(1). doi:<a href="https://doi.org/10.3390/mi13010017">10.3390/mi13010017</a>
  apa: Nirwan, J. S., Lou, S., Hussain, S., Nauman, M., Hussain, T., Conway, B. R.,
    &#38; Ghori, M. U. (2022). Electrically tunable lens (ETL) - based variable focus
    imaging system for parametric surface texture analysis of materials. <i>Micromachines</i>.
    MDPI. <a href="https://doi.org/10.3390/mi13010017">https://doi.org/10.3390/mi13010017</a>
  chicago: Nirwan, Jorabar Singh, Shan Lou, Saqib Hussain, Muhammad Nauman, Tariq
    Hussain, Barbara R. Conway, and Muhammad Usman Ghori. “Electrically Tunable Lens
    (ETL) - Based Variable Focus Imaging System for Parametric Surface Texture Analysis
    of Materials.” <i>Micromachines</i>. MDPI, 2022. <a href="https://doi.org/10.3390/mi13010017">https://doi.org/10.3390/mi13010017</a>.
  ieee: J. S. Nirwan <i>et al.</i>, “Electrically tunable lens (ETL) - based variable
    focus imaging system for parametric surface texture analysis of materials,” <i>Micromachines</i>,
    vol. 13, no. 1. MDPI, 2022.
  ista: Nirwan JS, Lou S, Hussain S, Nauman M, Hussain T, Conway BR, Ghori MU. 2022.
    Electrically tunable lens (ETL) - based variable focus imaging system for parametric
    surface texture analysis of materials. Micromachines. 13(1), 17.
  mla: Nirwan, Jorabar Singh, et al. “Electrically Tunable Lens (ETL) - Based Variable
    Focus Imaging System for Parametric Surface Texture Analysis of Materials.” <i>Micromachines</i>,
    vol. 13, no. 1, 17, MDPI, 2022, doi:<a href="https://doi.org/10.3390/mi13010017">10.3390/mi13010017</a>.
  short: J.S. Nirwan, S. Lou, S. Hussain, M. Nauman, T. Hussain, B.R. Conway, M.U.
    Ghori, Micromachines 13 (2022).
date_created: 2022-01-02T23:01:33Z
date_published: 2022-01-01T00:00:00Z
date_updated: 2023-08-09T10:16:10Z
day: '01'
ddc:
- '620'
department:
- _id: KiMo
doi: 10.3390/mi13010017
external_id:
  isi:
  - '000758547200001'
file:
- access_level: open_access
  checksum: 5d062cae3f1acb251cacb21021724c4e
  content_type: application/pdf
  creator: alisjak
  date_created: 2022-01-03T13:43:01Z
  date_updated: 2022-01-03T13:43:01Z
  file_id: '10601'
  file_name: 2021_Micromachines_Singh.pdf
  file_size: 5370675
  relation: main_file
  success: 1
file_date_updated: 2022-01-03T13:43:01Z
has_accepted_license: '1'
intvolume: '        13'
isi: 1
issue: '1'
keyword:
- surface texture
- electrically tunable lens
- materials
- hypromellose
- surface topography
- surface roughness
- pharmaceutical tablet
- variable focus imaging
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '01'
oa: 1
oa_version: Published Version
publication: Micromachines
publication_identifier:
  eissn:
  - 2072-666X
publication_status: published
publisher: MDPI
quality_controlled: '1'
scopus_import: '1'
status: public
title: Electrically tunable lens (ETL) - based variable focus imaging system for parametric
  surface texture analysis of materials
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 13
year: '2022'
...
---
OA_type: closed access
_id: '22549'
abstract:
- lang: eng
  text: "The time that rainfall takes to reach the outlet of a catchment as discharge
    (transit time) is a fundamental and\r\nintegrated measure of catchment hydrological
    processes and solute transport mechanisms. As such, many efforts\r\nhave been
    dedicated to its understanding and quantification. However, defining and ranking
    which factors,\r\ninternal and external to the system, control the distributions
    of transit time is still an open challenge. Here, we\r\ndevelop a two-stage approach
    to explore climate and topography controls on transit time, using a fully distributed
    hydrological model coupled with a transport component. Specifically, we apply
    the model to two\r\nsynthetic topographies under five observed climate regimes.
    With this setup, water fluxes from two years of daily\r\nrainfall events are singularly
    tracked across the catchments to then derive the distributions of transit time
    and\r\nfraction of young water for each combination of topography and climate.
    Results highlight a considerable\r\nvariability of transit times in all climates
    and a pronounced effect of topography within a given climate. They\r\nfurther
    reveal that for wet climates it is possible to define a curve describing water
    transit time as a function of\r\ncumulative discharge that only depends on topographic
    properties. On the contrary, in dry climates the variability of transit time and
    young water fraction is much larger and not amenable to a simple summary. Despite\r\nsimplifications,
    quantitative model-based inferences of transit time distributions are useful to
    better understand\r\nhow climate and topography affect catchment functioning."
article_processing_charge: No
article_type: original
author:
- first_name: Federica
  full_name: Remondi, Federica
  last_name: Remondi
- first_name: Martina
  full_name: Botter, Martina
  last_name: Botter
- first_name: Paolo
  full_name: Burlando, Paolo
  last_name: Burlando
- first_name: Simone
  full_name: Fatichi, Simone
  id: cf8e546b-a9b0-11f0-a43b-aa89ed1b56d6
  last_name: Fatichi
citation:
  ama: 'Remondi F, Botter M, Burlando P, Fatichi S. Variability of transit time distributions
    with climate and topography: A modelling approach. <i>Journal of Hydrology</i>.
    2019;569:37-50. doi:<a href="https://doi.org/10.1016/j.jhydrol.2018.11.011">10.1016/j.jhydrol.2018.11.011</a>'
  apa: 'Remondi, F., Botter, M., Burlando, P., &#38; Fatichi, S. (2019). Variability
    of transit time distributions with climate and topography: A modelling approach.
    <i>Journal of Hydrology</i>. Elsevier. <a href="https://doi.org/10.1016/j.jhydrol.2018.11.011">https://doi.org/10.1016/j.jhydrol.2018.11.011</a>'
  chicago: 'Remondi, Federica, Martina Botter, Paolo Burlando, and Simone Fatichi.
    “Variability of Transit Time Distributions with Climate and Topography: A Modelling
    Approach.” <i>Journal of Hydrology</i>. Elsevier, 2019. <a href="https://doi.org/10.1016/j.jhydrol.2018.11.011">https://doi.org/10.1016/j.jhydrol.2018.11.011</a>.'
  ieee: 'F. Remondi, M. Botter, P. Burlando, and S. Fatichi, “Variability of transit
    time distributions with climate and topography: A modelling approach,” <i>Journal
    of Hydrology</i>, vol. 569. Elsevier, pp. 37–50, 2019.'
  ista: 'Remondi F, Botter M, Burlando P, Fatichi S. 2019. Variability of transit
    time distributions with climate and topography: A modelling approach. Journal
    of Hydrology. 569, 37–50.'
  mla: 'Remondi, Federica, et al. “Variability of Transit Time Distributions with
    Climate and Topography: A Modelling Approach.” <i>Journal of Hydrology</i>, vol.
    569, Elsevier, 2019, pp. 37–50, doi:<a href="https://doi.org/10.1016/j.jhydrol.2018.11.011">10.1016/j.jhydrol.2018.11.011</a>.'
  short: F. Remondi, M. Botter, P. Burlando, S. Fatichi, Journal of Hydrology 569
    (2019) 37–50.
das_tickbox: '1'
date_created: 2026-07-27T12:30:24Z
date_published: 2019-02-01T00:00:00Z
date_updated: 2026-08-06T08:12:57Z
day: '01'
doi: 10.1016/j.jhydrol.2018.11.011
extern: '1'
intvolume: '       569'
keyword:
- Transit time distributions
- Young water
- Climate
- Topography
- Distributed hydrological modelling
language:
- iso: eng
month: '02'
oa_version: None
page: 37-50
publication: Journal of Hydrology
publication_identifier:
  eissn:
  - 1879-2707
  issn:
  - 0022-1694
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Variability of transit time distributions with climate and topography: A modelling
  approach'
type: journal_article
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
volume: 569
year: '2019'
...
---
OA_type: closed access
_id: '21516'
abstract:
- lang: eng
  text: The notion of elliptic or ellipsoidal conformal equivalent structure is introduced
    to model rough surface topography by use of convex homogenized shapes. The method
    is based on classical stereological results dealing with the relation between
    the number of intersections of an object with a set of parallel straight lines.
    The approach leads to an algorithm comparing the number of intercepts on both
    sampled surfaces and homogenized shapes selected for modeling. Some applications
    using the comparative values of the parameters of the homogenized structures are
    presented in this paper.
article_processing_charge: No
article_type: original
author:
- first_name: Charles
  full_name: Roques-Carmes, Charles
  id: e2e68fc9-6505-11ef-a541-eb4e72cc3e82
  last_name: Roques-Carmes
- first_name: N.
  full_name: Bodin, N.
  last_name: Bodin
- first_name: G.
  full_name: Monteil, G.
  last_name: Monteil
- first_name: J.F.
  full_name: Quiniou, J.F.
  last_name: Quiniou
citation:
  ama: 'Roques-Carmes C, Bodin N, Monteil G, Quiniou JF. Description of rough surfaces
    using conformal equivalent structure concept: Part 1. Stereological approach.
    <i>Wear</i>. 2001;248(1-2):82-91. doi:<a href="https://doi.org/10.1016/s0043-1648(00)00562-7">10.1016/s0043-1648(00)00562-7</a>'
  apa: 'Roques-Carmes, C., Bodin, N., Monteil, G., &#38; Quiniou, J. F. (2001). Description
    of rough surfaces using conformal equivalent structure concept: Part 1. Stereological
    approach. <i>Wear</i>. Elsevier. <a href="https://doi.org/10.1016/s0043-1648(00)00562-7">https://doi.org/10.1016/s0043-1648(00)00562-7</a>'
  chicago: 'Roques-Carmes, Charles, N. Bodin, G. Monteil, and J.F. Quiniou. “Description
    of Rough Surfaces Using Conformal Equivalent Structure Concept: Part 1. Stereological
    Approach.” <i>Wear</i>. Elsevier, 2001. <a href="https://doi.org/10.1016/s0043-1648(00)00562-7">https://doi.org/10.1016/s0043-1648(00)00562-7</a>.'
  ieee: 'C. Roques-Carmes, N. Bodin, G. Monteil, and J. F. Quiniou, “Description of
    rough surfaces using conformal equivalent structure concept: Part 1. Stereological
    approach,” <i>Wear</i>, vol. 248, no. 1–2. Elsevier, pp. 82–91, 2001.'
  ista: 'Roques-Carmes C, Bodin N, Monteil G, Quiniou JF. 2001. Description of rough
    surfaces using conformal equivalent structure concept: Part 1. Stereological approach.
    Wear. 248(1–2), 82–91.'
  mla: 'Roques-Carmes, Charles, et al. “Description of Rough Surfaces Using Conformal
    Equivalent Structure Concept: Part 1. Stereological Approach.” <i>Wear</i>, vol.
    248, no. 1–2, Elsevier, 2001, pp. 82–91, doi:<a href="https://doi.org/10.1016/s0043-1648(00)00562-7">10.1016/s0043-1648(00)00562-7</a>.'
  short: C. Roques-Carmes, N. Bodin, G. Monteil, J.F. Quiniou, Wear 248 (2001) 82–91.
date_created: 2026-03-30T12:22:47Z
date_published: 2001-03-01T00:00:00Z
date_updated: 2026-04-15T13:21:44Z
day: '01'
ddc:
- '530'
doi: 10.1016/s0043-1648(00)00562-7
extern: '1'
intvolume: '       248'
issue: 1-2
keyword:
- Rough surface topography
- Stereology
- Algorithm
- Equivalent structure concept
language:
- iso: eng
month: '03'
oa_version: None
page: 82-91
publication: Wear
publication_identifier:
  eissn:
  - 1873-2577
  issn:
  - 0043-1648
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Description of rough surfaces using conformal equivalent structure concept:
  Part 1. Stereological approach'
type: journal_article
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
volume: 248
year: '2001'
...
---
OA_type: closed access
_id: '21517'
abstract:
- lang: eng
  text: In our new approach, the notion of conformal equivalent structure is introduced
    by comparing the slope or gradient distributions of surface topography in 2D or
    3D mode, respectively. The stereological approach described in Section 2 is, thus,
    confirmed by the numerical one which is proposed in this paper. The approach emphasizes
    the viability of the modeling and the limits observed in some practical applications
    of the study of rough surfaces via different approximation methods. The few divergences
    which have been noticed may be explained by the introduction of parameters such
    as skewness and kurtosis.
article_processing_charge: No
article_type: original
author:
- first_name: Charles
  full_name: Roques-Carmes, Charles
  id: e2e68fc9-6505-11ef-a541-eb4e72cc3e82
  last_name: Roques-Carmes
- first_name: N.
  full_name: Bodin, N.
  last_name: Bodin
- first_name: G.
  full_name: Monteil, G.
  last_name: Monteil
- first_name: J.F.
  full_name: Quiniou, J.F.
  last_name: Quiniou
citation:
  ama: 'Roques-Carmes C, Bodin N, Monteil G, Quiniou JF. Description of rough surfaces
    using conformal equivalent structure concept: Part 2. Numerical approach. <i>Wear</i>.
    2001;248(1-2):92-99. doi:<a href="https://doi.org/10.1016/s0043-1648(00)00563-9">10.1016/s0043-1648(00)00563-9</a>'
  apa: 'Roques-Carmes, C., Bodin, N., Monteil, G., &#38; Quiniou, J. F. (2001). Description
    of rough surfaces using conformal equivalent structure concept: Part 2. Numerical
    approach. <i>Wear</i>. Elsevier. <a href="https://doi.org/10.1016/s0043-1648(00)00563-9">https://doi.org/10.1016/s0043-1648(00)00563-9</a>'
  chicago: 'Roques-Carmes, Charles, N. Bodin, G. Monteil, and J.F. Quiniou. “Description
    of Rough Surfaces Using Conformal Equivalent Structure Concept: Part 2. Numerical
    Approach.” <i>Wear</i>. Elsevier, 2001. <a href="https://doi.org/10.1016/s0043-1648(00)00563-9">https://doi.org/10.1016/s0043-1648(00)00563-9</a>.'
  ieee: 'C. Roques-Carmes, N. Bodin, G. Monteil, and J. F. Quiniou, “Description of
    rough surfaces using conformal equivalent structure concept: Part 2. Numerical
    approach,” <i>Wear</i>, vol. 248, no. 1–2. Elsevier, pp. 92–99, 2001.'
  ista: 'Roques-Carmes C, Bodin N, Monteil G, Quiniou JF. 2001. Description of rough
    surfaces using conformal equivalent structure concept: Part 2. Numerical approach.
    Wear. 248(1–2), 92–99.'
  mla: 'Roques-Carmes, Charles, et al. “Description of Rough Surfaces Using Conformal
    Equivalent Structure Concept: Part 2. Numerical Approach.” <i>Wear</i>, vol. 248,
    no. 1–2, Elsevier, 2001, pp. 92–99, doi:<a href="https://doi.org/10.1016/s0043-1648(00)00563-9">10.1016/s0043-1648(00)00563-9</a>.'
  short: C. Roques-Carmes, N. Bodin, G. Monteil, J.F. Quiniou, Wear 248 (2001) 92–99.
date_created: 2026-03-30T12:22:47Z
date_published: 2001-03-01T00:00:00Z
date_updated: 2026-04-15T12:28:09Z
day: '01'
doi: 10.1016/s0043-1648(00)00563-9
extern: '1'
intvolume: '       248'
issue: 1-2
keyword:
- Rough surface topography
- Equivalent structure concept
language:
- iso: eng
month: '03'
oa_version: None
page: 92-99
publication: Wear
publication_identifier:
  eissn:
  - 1873-2577
  issn:
  - 0043-1648
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Description of rough surfaces using conformal equivalent structure concept:
  Part 2. Numerical approach'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 248
year: '2001'
...