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Article
Publication date: 8 January 2018

Yuxin Miao, Guofeng Pan, Caixuan Sun, Ping He, Guanlong Cao, Chao Luo, Li Zhang and Hongliang Li

The purpose of this paper is to study the effect of doping, annealing temperature and visible optical excitation on CuO-ZnO nanocomposites’ acetone sensing properties and…

Abstract

Purpose

The purpose of this paper is to study the effect of doping, annealing temperature and visible optical excitation on CuO-ZnO nanocomposites’ acetone sensing properties and introduce an attractive candidate for acetone detection at about room temperature.

Design/methodology/approach

ZnO nanoparticles doped with CuO were prepared by sol-gel method, and the structure and morphology were characterized via X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy and Brunauer-Emmett-Teller. The photoelectric responses of CuO-ZnO nanocomposites to cetone under the irradiation of visible light were investigated at about 30°C. The photoelectric response mechanism was also discussed with the model of double Schottky.

Findings

The doping of CuO enhanced performance of ZnO nanoparticles in terms of the photoelectric responses and the gas response and selectivity to acetone of ZnO nanoparticles, in addition, decreasing the operating temperature to about 30ºC. The optimum performance was obtained by 4.17% CuO-ZnO nanocomposites. Even at the operating temperature, about 30ºC, the response to 1,000 ppm acetone was significantly increased to 579.24 under the visible light irradiation.

Practical implications

The sensor fabricated by 4.17% CuO-ZnO nanocomposites exhibited excellent acetone-sensing characteristics at about 30ºC. It is promising to be applied in low power and miniature acetone gas sensors.

Originality/value

In the present research, a new nanocomposite material of CuO-ZnO was prepared by Sol-gel method. The optimum gas sensing properties to acetone were obtained by 4.17% CuO-ZnO nanocomposites at about 30ºC operating temperature when it was irradiated by visible light with the wavelength more than 420 nm.

Details

Sensor Review, vol. 38 no. 3
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 7 November 2016

Swee-Yong Pung, Yim-Leng Chan, Srimala Sreekantan and Fei-Yee Yeoh

The purpose of this study is to synthesize a semiconductor photocatalyst which responds to both UV light and visible light in removal of organic dyes.

Abstract

Purpose

The purpose of this study is to synthesize a semiconductor photocatalyst which responds to both UV light and visible light in removal of organic dyes.

Design/methodology/approach

ZnO nanoparticles were pre-synthesised via sol-gel method using zinc nitrate tetrahydrate and methanamine at 90°C for 20 h. Subsequently, the as-synthesised ZnO nanoparticles were filtered, washed and dried. To synthesize ZnO-MnO2 core shell nanocomposites (CSNs), 2:3 M ratio of KMnO4 and MnSO4 solution was stirred for an hour. Next, ZnO nanoparticles were added into the solution. The solution was heated at 160°C for 3 h for the formation of ZnO-MnO2 CSNs. The structural, optical and photocatalytic properties of ZnO-MnO2 CSNs were characterised by field emission scanning electron microscope, transmission electron microscopy (TEM), X-ray diffractometer and PL spectroscopy, respectively.

Findings

The photodegradation efficiencies of rhodamine B (RhB) dye by ZnO-MnO2 CSNs as photocatalysts are 87.1 per cent under UV irradiation and 76.6 per cent under visible light irradiation, respectively. Their corresponding rate constants are 0.016 min−1 under UV irradiation and 0.013 min−1 under visible light irradiation. It can be concluded that N-deethylation was the dominant step during the photodegradation of RhB dye as compared to cycloreversion. The ZnO-MnO2 CSNs demonstrated good photostability after three consecutive runs.

Originality/value

ZnO-MnO2 CSN photocatalyst which could response to UV and visible light in degradation of RhB dye was synthesised using sol-gel method. The analysis shows that N-deethylation was the key photodegradation mechanism of RhB by ZnO-MnO2 CSN.

Details

Pigment & Resin Technology, vol. 45 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 2 January 2018

Wei-Ting Chang, Huang-Jan Hsu, Cho-Pei Jiang, Shyh-Yuan Lee and Yuan-Min Lin

The aim of this paper is to examine the effects of light controlling system that combined high refractive particles (n-TiO2 [titanium dioxide – TiO2]) and tartrazine lake…

Abstract

Purpose

The aim of this paper is to examine the effects of light controlling system that combined high refractive particles (n-TiO2 [titanium dioxide – TiO2]) and tartrazine lake dye (TL dye) on thickness, flexural strength, flexural modulus and surface details of the 3D-printed resin.

Design/methodology/approach

Influences of different concentrations of n-TiO2 and TL dye in light-cured resin formulations for 3D printing (3DP) application were evaluated, including curing thickness, flexural strength and surface details under scanning electron microscopy.

Findings

The polymerization thickness of samples containing both n-TiO2 and TL dye was lower compared to samples with TL dye solely. Samples containing more n-TiO2 and more TL dye exhibited lower flexural strength and modulus. Ramp models showed that for samples containing 1 per cent TL dye, when their n-TiO2 content increased from 1 to 5 per cent, surface laminate structures became sharper. However, when the TL dye content doubled to 2 per cent, the surface laminate structures were indefinite compared to 1 per cent TL dye-containing counterparts.

Originality value

In visible-light 3DP, light controlling system in cooperate dye with high refractive particles provides better energy distribution and scattering control. High refractive particles, dyes and light exposure time had influenced the surface resolution and mechanical properties of the 3DP products.

Details

Rapid Prototyping Journal, vol. 24 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

Content available
Article
Publication date: 9 January 2009

Abstract

Details

Pigment & Resin Technology, vol. 38 no. 1
Type: Research Article
ISSN: 0369-9420

Content available
Article
Publication date: 6 February 2009

Abstract

Details

Soldering & Surface Mount Technology, vol. 21 no. 1
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 11 April 2021

Yifan Xu, Xiang Gu, Qinghua Meng, Bin Wang and Jun Fan

This paper aims to show a series of hydrogels with adjustable mechanical properties, which can be cured quickly with visible light. The hydrogel is prepared conveniently…

Abstract

Purpose

This paper aims to show a series of hydrogels with adjustable mechanical properties, which can be cured quickly with visible light. The hydrogel is prepared conveniently with hydroxyethyl acrylate, cross-linker, gelatin and photoinitiator, and can be printed into certain 3D patterns with the direct ink write (DIW) 3D printer designed and developed by the research group.

Design/methodology/approach

In this paper, the authors designed a composite sensitization initiation system that is suitable for hydrogels. The concentration of photoinitiator, gelatin and cross-linker was studied to optimize the curing efficiency and adjust the mechanical properties. A DIW 3D printer was designed for the printing of hydrogel. Pre-gel solution was loaded into printer for printing into established models. The models were made and sliced with software.

Findings

The hydrogels can be cured efficiently with 405-nm visible light. While adding various content of gelatin and cross-linker, the mechanical properties of hydrogels show from soft and fragile (elastic modulus of 121.18 kPa and work of tension of 218.11 kJ·m−3) to rigid and tough (elastic modulus of 505.15 kPa and work of tension of 969.00 kJ·m−3). The hydrogels have high capacity of water absorption. With the DIW 3D printer, pre-gel hydrogel solution can be printed into objects with certain dimension.

Originality/value

In this work, a composite sensitization initiation system was designed, and fast curing hydrogels with adjustable mechanical properties had been prepared conveniently, which has high equilibrium water content and 3D printability with the DIW 3D printer.

Details

Rapid Prototyping Journal, vol. 27 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 8 March 2021

Wenjie Wang, Mengran Zhang, Binxia Zhao, Linxue Liu, Ruixuan Han and Nan Wang

The purpose of this paper is to improve the degradation efficiency of Rhodamine B (RhB) by new photocatalytic materials.

Abstract

Purpose

The purpose of this paper is to improve the degradation efficiency of Rhodamine B (RhB) by new photocatalytic materials.

Design/methodology/approach

Binary Z-scheme g-C3N4/Bi2WO6 photocatalytic material was synthesized by the one-step hydrothermal reaction. The construction of Z-scheme heterojunction led to the rapid separation of photogenerated electrons and holes, which would degrade RhB into small molecular substances to achieve the purpose of degradation.

Findings

It was found that Bi2WO6/25%g-C3N4 displayed the highest photocatalytic activity, which was about 1.44 and 1.34 times higher than that of pure Bi2WO6 and g-C3N4, respectively. According to the trapping experiments, the superoxide radical (·O2−) was the major active species of the RhB decomposition in Bi2WO6/g-C3N4 catalysts.

Originality/value

The successful synthesis of Z-scheme Bi2WO6/g-C3N4 provides new ideas and references for the design of catalysts with high photocatalytic activity, which should have wide applications in the future.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 27 July 2018

Shao Rui Chen

The purpose of this study is to investigate the effect of the spacer length of zinc porphyrin-TiO2 hybrids by photodegradation of methyl orange (MO) in aqueous solution…

Abstract

Purpose

The purpose of this study is to investigate the effect of the spacer length of zinc porphyrin-TiO2 hybrids by photodegradation of methyl orange (MO) in aqueous solution under visible light.

Design/methodology/approach

5-Mono-[4-hydroxyphenyl]-10,15,20-triphenylporphyrin was synthesized using Alder method. A new series of porphyrins and their corresponding zinc complexes (ZnPp) were obtained from 5-mono-[4-hydroxyphenyl]-10,15,20-triphenylporphyrin via nucleophilic substitution reaction. The ZnPp-TiO2 photocatalysts were prepared by loading ZnPp onto TiO2 and characterized by scanning electron microscope, X-ray diffraction, UV-vis diffuse reflectance spectrum and X-ray photoelectron spectroscopy.

Findings

The results indicated that zinc porphyrins were successfully loaded on the surface of TiO2 microsphere, which is crucial to enhance the activity of the catalytic composite under visible light. All the novel photocatalysts showed much enhanced photoactivity than bare TiO2. Among all the prepared ZnPp-TiO2, 5,10,15-triphenyl-20-[4-(4-naphthoxy)-butoxy]phenyl zinc porphyrin-TiO2 (4b) showed the highest photocatalytic activity for the degradation of MO.

Research limitations/implications

Synthesis of these zinc porphyrins had never been reported previously.

Originality/value

Four novel zinc porphyrin-TiO2 photocatalysts which could response to visible light in degradation of MO were synthesized using Alder method. The results show that the photocatalytic activity of 5,10,15-triphenyl-20-[4-(4-naphthoxy)butoxy] phenyl zinc porphyrin- TiO2 is higher than others.

Details

Pigment & Resin Technology, vol. 47 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 7 December 2015

Kathryn Anne Denny

Closed circuit television (CCTV) imaging is an increasingly used technology and it is now common place for law enforcement to access CCTV footage as an investigative tool…

Abstract

Purpose

Closed circuit television (CCTV) imaging is an increasingly used technology and it is now common place for law enforcement to access CCTV footage as an investigative tool to assist in the nomination of a person of interest, or to aid in the prosecution of an offender. The purpose of this paper is to discuss the role of imaging practitioners in the analysis and interpretation of CCTV images within a law enforcement context. It explores and addresses the limitations of CCTV imaging in evidence with a focus on the interpretation of changes in the visual representation of clothing items.

Design/methodology/approach

This paper demonstrates the variations observed in four dark toned garments imaged using one CCTV camera with two different recording settings – visible light and near infrared. The device used was installed and operated in a manner comparable to that used in the public domain, the resulting images indicative of those experienced in casework.

Findings

The results display a noticeable change to the tonality of each clothing item between the varied recording conditions. These inconsistencies highlight the limitations of layperson analysis and identify the importance of the inclusion of imaging practitioners when interpreting and analysing such images as evidence.

Originality/value

With an abundance of images in the society, layperson interpretation has become common place. Recognising the value of trained imaging practitioners who can assist law enforcement in analysis and interpretation is paramount to ensuring CCTV images as evidence are used appropriately.

Details

Journal of Criminological Research, Policy and Practice, vol. 1 no. 4
Type: Research Article
ISSN: 2056-3841

Keywords

Content available
Article
Publication date: 29 May 2007

Abstract

Details

Pigment & Resin Technology, vol. 36 no. 3
Type: Research Article
ISSN: 0369-9420

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