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Article
Publication date: 23 May 2008

D. Veselý and A. Kalendová

The purpose of this paper is to describe the process of synthesizing lamellarly‐shaped anticorrosion pigments having a chemically active layer whose core consists of metal…

Abstract

Purpose

The purpose of this paper is to describe the process of synthesizing lamellarly‐shaped anticorrosion pigments having a chemically active layer whose core consists of metal aluminium on which a thin spinel film is synthesised.

Design/methodology/approach

Anticorrosion pigments were synthesised by reaction of metal aluminium lamellar particles whose surface was oxidised to Al2O3 during the first stage and by subsequent reaction with ZnO and/or MgO at 800‐1,150°C producing a thin spinel layer that is chemically bonded to the metal core of the pigment particles. Core‐shell pigments including MgAl2O4/Al, Mg0.8Zn0.2Al2O4/Al, Mg0.6Zn0.4Al2O4/Al, Mg0.4Zn0.6Al2O4/Al, Mg0.2Zn0.8Al2O4/Al and ZnAl2O4/Al were synthesised. The prepared pigments were characterised by means of X‐ray diffraction analysis and scanning electron microscopy. The synthesised anticorrosion pigments were used to prepare epoxy coatings that were tested upon application for their anticorrosion properties and resistance against a chemical environment.

Findings

The lamellar shape of the particles, as well as good‐quality coverage with a thin spinel layer, was identified in the prepared pigments. All of the synthesised pigments exhibit good anticorrosion efficiency in epoxy coatings. Compared to lamellar kaolin and metal core of aluminium without coverage, the protective function of the synthesised pigments in coatings is demonstrably better.

Practical implications

The synthesised pigments find convenient applications in coatings protecting metal bases from corrosion.

Originality/value

Synthesis of a spinel layer on the metal core of aluminium is a novel method; so is the application of these substances in coatings designed for the protection of metals from corrosion. Of great benefit is the fact that the synthesised pigments are free of any substances harmful to the environment.

Details

Pigment & Resin Technology, vol. 37 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 March 1997

Kamal T. Hindy

Investigates the characterization of cement dust collected by electrostatic precipitators and fabric filters to study its ability to be used as a concrete material. The…

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Abstract

Investigates the characterization of cement dust collected by electrostatic precipitators and fabric filters to study its ability to be used as a concrete material. The study includes 26 cement dust samples collected from different points on dry process lines in four of the major cement plants in the United Arab Emirates. The collected samples were subjected to detailed physical tests and chemical analyses. Results obtained were compared with the British Standard Specifications set for ordinary Portland cement. Finds that eight samples show comparable physical properties and chemical as well as mineral composition.

Details

Environmental Management and Health, vol. 8 no. 1
Type: Research Article
ISSN: 0956-6163

Keywords

Article
Publication date: 5 May 2015

Salwa H El-Sabbagh, Doaa S. Mahmoud, M. F. Zawrah, Nivin M. Ahmed and Magdy W. Sabaa

The purpose of this paper is to evaluate the efficiency of organobentonite (OB) as reinforcing filler in acrylonitrile-butadiene rubber (NBR). The composites were prepared…

Abstract

Purpose

The purpose of this paper is to evaluate the efficiency of organobentonite (OB) as reinforcing filler in acrylonitrile-butadiene rubber (NBR). The composites were prepared using different loadings of OB and studying in details their properties. A series of OB was modified using surfactant N-cetyl-N, N, N-trimethyl ammonium bromide (CTAB) with concentrations 0.5, 1 and 2 cation exchange capacity (CEC) of bentonite.

Design/methodology/approach

The different bentonites were characterized using different analytical and spectro-photometric techniques, such as infra red, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy, while rubber vulcanizate rheological, morphological, swelling and thermal properties were examined using different standard instrumental testing and methods.

Findings

The study revealed that the modification of bentonite using CTAB showed significant enhancement on NBR properties, and the optimum filler loading was 12 phr for both 0.5CEC OB and 2CEC OB. These modified bentonites improved reinforcing properties to NBR vulcanizates. Also, results showed that composites exhibited remarkable improvements in tensile strength, elongation at break and hardness in the presence of modified bentonite and also an increase in thermal stability.

Research limitations/implications

Na-B cannot be applied in rubber matrix without modification because it is incompatible with it.

Practical implications

The modified bentonite is considered as efficient reinforcing filler which can replace other fillers because it has lower surface energy and improved intercalating behaviour in rubber matrix.

Originality/value

These papered bentonites are cheap with relatively high purity, which make rubber/clay composites emerge as new class of material and can be used in different fields other than rubber.

Article
Publication date: 4 September 2017

Ismahen Essaidi, Ahmed Snoussi, Hayet Ben Haj Koubaier, Hervé Casabianca and Nabiha Bouzouita

The paper aims to analyse the effect of acid hydrolysis on the chemical composition and the biological activities of Rubia tinctorum collected from the south of Tunisia…

Abstract

Purpose

The paper aims to analyse the effect of acid hydrolysis on the chemical composition and the biological activities of Rubia tinctorum collected from the south of Tunisia. It proposes to clarify the relationship between alizarin content and the antioxidant and antimicrobial activities of Rubia extract.

Design/methodology/approach

The paper opted for analytical tools (HPLC) and the in-vitro study of biological activities, namely, the antioxidant activity which is evaluated using the radical scavenging assay (ABTS) and ferric reducing power assay (FRAP); the antimicrobial activity is tested using the wells agar diffusion method.

Findings

The paper provides information about the positive effect of acid hydrolysis, namely, the enhancement of alizarin content in the extract which has increased its antioxidant and antimicrobial activities.

Originality/value

This paper fulfils an identified need to study the relationship between the chemical composition, biological activities and colour enhancement.

Details

Pigment & Resin Technology, vol. 46 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 28 August 2007

C.A. Smith

The purpose of the paper is to discuss the chemical characterisation of inorganic and organic materials found in electronic systems.

Abstract

Purpose

The purpose of the paper is to discuss the chemical characterisation of inorganic and organic materials found in electronic systems.

Design/methodology/approach

The paper provides an introduction to Fourier transform infrared spectroscopy, which is used for the chemical characterisation and analysis of materials. Examples from recent case studies are given to illustrate the work.

Findings

It was found that Fourier transform infrared spectroscopy can successfully identify materials at various stages of their lifecycle. By this means any contaminants and their resulting detrimental effects can be eliminated.

Originality/value

The paper demonstrates how the chemical analysis of a material is conducted, and what can be learned from the investigation.

Details

Circuit World, vol. 33 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 March 2005

Peter Meeh

This paper describes a state‐of‐the‐art process for immersion tin plating of PCBs which is used to preserve solderability prior to assembly. The process sequence is…

Abstract

This paper describes a state‐of‐the‐art process for immersion tin plating of PCBs which is used to preserve solderability prior to assembly. The process sequence is described and preventive measures for handling the final surface finish is documented. A solderability test method and basic requirements for fluxes and soldering parameters are also described. Quantitative results on the formation of intermetallic tin‐copper phases are shown and their influence on the formation of tin whiskers explained. A problem in production is the precise measurement of the tin thickness, therefore different measuring methods are also detailed. Finally, the mechanism of tin deposition and the formation of tetravalent tin and the relationship with bath age and deposit quality are discussed.

Details

Circuit World, vol. 31 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

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…

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

Keywords

Article
Publication date: 1 March 1956

B.W. Neumaier and C.M. Schillmoller

Efforts to avoid low‐temperature hydrogen attack at a new fluid catalytic cracking unit of the Richfield Oil Corporation, Wilmington, Calif., have been successful as a…

Abstract

Efforts to avoid low‐temperature hydrogen attack at a new fluid catalytic cracking unit of the Richfield Oil Corporation, Wilmington, Calif., have been successful as a result of corrosion prevention in the design stage and corrosion control during operation. When the unit was shut down recently after more than a year of successful and continuous operation it was found to be in excellent condition. The following is the first half of a paper presented before the American Petroleum Institute's Refining Division last year and before the National Institute of Corrosion Engineers' Annual Meeting this year. The authors describe the different forms of hydrogen damage and the prevention steps that were taken. Preliminary evaluation by hydrogen probes, painted‐can tests and chemical analyses were employed to detect any hydrogen penetration taking place before the routine shut‐down enabled

Details

Anti-Corrosion Methods and Materials, vol. 3 no. 3
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 11 September 2009

Zaker Bahreini

The purpose of this paper is to synthesise, characterise and find out properties of some new arylazopyridone disperse dyes, bearing different substituents on coupling…

Abstract

Purpose

The purpose of this paper is to synthesise, characterise and find out properties of some new arylazopyridone disperse dyes, bearing different substituents on coupling component of the dyes.

Design/methodology/approach

The dyes are synthesised by diazotisation, coupling and cyclization reactions, starting from various aryldiazonium salts and different β‐diketoesters followed by condensation with cyanoacetamide. The structures of these dyes are characterised and confirmed by melting point, elemental analysis, infrared, ultraviolet‐visible spectroscopy (UV/VIS) and nuclear magnetic resonance (1H‐NMR) data. Their absorption properties in different solvents are also investigated.

Findings

The wavelength of maximum absorptions, molar extinction coefficients are strongly dependent on the electron donating ability of the substituents on the coupling moiety. The absorption bands of these dyes move towards longer wavelength as the polarity of the solvents and electron density of substituents on the coupling moiety increase. These dyes are chromophorically strong as evidenced by molar extinction coefficient in solvents.

Originality/value

In this paper, four series of arylazopyridone dyes (21 dyes) are synthesised and characterised. They have not been registered in the literature previously.

Details

Pigment & Resin Technology, vol. 38 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 22 October 2021

Na Pang, Li Qian, Weimin Lyu and Jin-Dong Yang

In computational chemistry, the chemical bond energy (pKa) is essential, but most pKa-related data are submerged in scientific papers, with only a few data that have been…

Abstract

Purpose

In computational chemistry, the chemical bond energy (pKa) is essential, but most pKa-related data are submerged in scientific papers, with only a few data that have been extracted by domain experts manually. The loss of scientific data does not contribute to in-depth and innovative scientific data analysis. To address this problem, this study aims to utilize natural language processing methods to extract pKa-related scientific data in chemical papers.

Design/methodology/approach

Based on the previous Bert-CRF model combined with dictionaries and rules to resolve the problem of a large number of unknown words of professional vocabulary, in this paper, the authors proposed an end-to-end Bert-CRF model with inputting constructed domain wordpiece tokens using text mining methods. The authors use standard high-frequency string extraction techniques to construct domain wordpiece tokens for specific domains. And in the subsequent deep learning work, domain features are added to the input.

Findings

The experiments show that the end-to-end Bert-CRF model could have a relatively good result and can be easily transferred to other domains because it reduces the requirements for experts by using automatic high-frequency wordpiece tokens extraction techniques to construct the domain wordpiece tokenization rules and then input domain features to the Bert model.

Originality/value

By decomposing lots of unknown words with domain feature-based wordpiece tokens, the authors manage to resolve the problem of a large amount of professional vocabulary and achieve a relatively ideal extraction result compared to the baseline model. The end-to-end model explores low-cost migration for entity and relation extraction in professional fields, reducing the requirements for experts.

Details

Data Technologies and Applications, vol. 56 no. 2
Type: Research Article
ISSN: 2514-9288

Keywords

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