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Article
Publication date: 1 January 2014

Shuo Liu, Jimin Feng, Jungang Lv and Wen Zhang

Ballpoint pen ink analysis is important for forensic scientist which can collect valuable information on questioned document. Inks widely used now constitute many substances to…

296

Abstract

Purpose

Ballpoint pen ink analysis is important for forensic scientist which can collect valuable information on questioned document. Inks widely used now constitute many substances to improve needed ink characteristics, including the coloring material (dyes or pigments), inks, solvents and resins. The complex components of the inks confront forensic ink chemists with a big challenge to carry out this analysis. However, because of the great importance of determining whether two pieces of written text originated from the same ink, therefore, comparison of different writing inks on a document to forensic scientist, many techniques have been tentatively employed in the ink analysis. In this study, Raman microscope was employed successfully in the analysis of inks. The paper aims to discuss these issues.

Design/methodology/approach

Damped or wet samples cannot be analyzed by IR if dehydration is not carried out FTIR observation, because of the extremely strong absorbance of water. Raman spectroscopy can cover the shortage of FTIR spectroscopy because water has weak absorbance in Raman spectroscopy. Raman shifts can give extra peak information because it usually has different positions with FTIR spectroscopy. A Renishaw inVia confocal Raman microscope system with two lasers emitting at 532/633 nm, charge-coupled device detector was employed collecting the Raman spectrum. Laser was chosen for emission in 1-100 percent power depending on the proper energy to get signal strong enough and protect the samples from burning. At least triple-tests were performed for each sample.

Findings

The result indicated that Raman spectroscopy could easily remove the interference caused by the paper which could hardly be removed with infrared spectroscopy. No sample preparation was required and only 30 s was needed for each sample in the optimized method. The method proved to be fast, accurate, non-destructive and could be easily applied to the real cases. The primary survey on inks from different market indicated five kinds of inks could be identified. The indicative peaks of each kind of ink (693, 1,150-1,210, 1,280-1,300, 1,360-1,400 and 1,531 cm−1) were summarized. The distributions of the inks in markets were also illustrated. Ink using alkyd resin as connecting materials or copper phthalocyanine as pigment decreased significantly. The data in this study would be helpful for the forensic scientists to identify these inks and examine the questioned document.

Originality/value

No previous studies on the analysis of inks in China market were found to the authors’ best, so the forensic scientists have no idea about the method using Raman for discrimination which proved to be effective, accurate and fast, the indicative peaks of each inks, the distributions in the markets, and therefore, the possibility to encounter specific ink in cases The data in this study would be helpful for the forensic scientists to identify these inks and examine the questioned document.

Details

Pigment & Resin Technology, vol. 43 no. 1
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 4 June 2024

Chunjie Wei, Qi Chen, Jimin Xu, Xiaojun Liu and Wei Wang

The purpose of this paper is to explore the operating characteristics of gallium-based liquid metals (GLMs) by directly adding them as lubricants in real mechanical equipment.

86

Abstract

Purpose

The purpose of this paper is to explore the operating characteristics of gallium-based liquid metals (GLMs) by directly adding them as lubricants in real mechanical equipment.

Design/methodology/approach

This paper conducts an analysis of the rotor-bearing system under GLM lubrication using a constructed test rig, focusing on vibration signals, surface characteristics of the friction pair, contact resistance and temperature rise features.

Findings

The study reveals that GLM can effectively improve the lubrication condition of the tribo-pair, leading to a more stable vibration signal in the system. Surface analysis demonstrates that GLM can protect the sample surface from wear, and phase separation occurs during the experimental process. Test results of contact resistance indicate that, in addition to enhancing the interfacial conductivity, GLM also generates a fluid dynamic pressure effect. The high thermal conductivity and anti-wear effects of GLM can reduce the temperature rise of the tribo-pair, but precautions should be taken to prevent oxidation and the loss of its fluidity.

Originality/value

The overall operating characteristics of the rotor-bearing system under GLM lubrication were investigated to provide new ideas for the lubrication of the rotor-bearing system.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2024-0067/

Details

Industrial Lubrication and Tribology, vol. 76 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

Available. Content available
Book part
Publication date: 28 July 2021

Mark Harvey

Abstract

Details

Climate Emergency
Type: Book
ISBN: 978-1-80043-333-5

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