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Article
Publication date: 3 January 2017

Khasan S. Karimov, Zubair Ahmad, Noshin Fatima, Muhammad Mansoor Ahmed and Muhammad Abid

The paper aims to study the effects of humidity on the electrical properties of copper phthalocyanine (CuPc) thin films deposited at different gravity conditions.

Abstract

Purpose

The paper aims to study the effects of humidity on the electrical properties of copper phthalocyanine (CuPc) thin films deposited at different gravity conditions.

Design/methodology/approach

Surface-type samples were fabricated on glass substrates with preliminary-deposited copper electrodes. The CuPc solution was prepared in benzene. The thin films of CuPc were deposited on these substrates at diverse gravity conditions by drop-casting and centrifugation at 1 × g and 70 × g, respectively. Impedance and capacitance of the fabricated devices were measured against the different relative humidity ranging from 32 to 98 per cent.

Findings

The impedance and the capacitance of the CuPc film were found to be dependent on the ambient humidity levels (32-98 per cent) and the gravity conditions (1 × g and 70 × g) opted during the fabrication process.

Research limitations/implications

The centrifugation technique can potentially be used in the instrumentation industry for the fabrication of humidity sensors.

Practical implications

The results of the investigations can potentially be used in the instrumentation and optoelectronics industry for the fabrication of humidity sensors.

Originality/value

CuPc films were deposited from a solution in benzene using drop-casting and centrifugation. The electrical properties of the films were found to be dependent on film fabrication conditions and ambient humidity levels. Growth-dependent electrical properties of the CuPc films can be explained by considering their structure.

Details

Pigment & Resin Technology, vol. 46 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 31 January 2023

Zhixiang Li, Shuo Han, Lei Wang and Kunhong Hu

This study aims to investigate the catalytic performance and tribological properties of MoS2 powder.

Abstract

Purpose

This study aims to investigate the catalytic performance and tribological properties of MoS2 powder.

Design/methodology/approach

In this work, the authors attempted to use MoS2 nanoparticles (nano-MoS2) as a catalyst to synthesize trimethylolpropane oleate (TMPTO) by esterification of trimethylolpropane and oleic acid. The small amount of highly dispersed nano-MoS2 catalyst remaining in TMPTO needed not to be separated and could be used as a lubricant modifier directly to achieve the purpose of improving the lubricity performance of TMPTO.

Findings

The results demonstrated that nano-MoS2 had good catalytic esterification ability and achieved in situ dispersion of about 0.191% nano-MoS2 in TMPTO while catalyzing the synthesis of base oil. After high-speed centrifugal sedimentation treatment, the product TMPTO still retained about 0.008% of nano-MoS2. The above-synthesized TMPTO has significantly better lubricity performance than commercially available TMPTO, in which the friction coefficient and wear rate could be reduced by 75%.

Originality/value

The results of this study provide an idea for the design of catalysts for ester oil synthesis.

Details

Industrial Lubrication and Tribology, vol. 75 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 7 October 2019

Hui Yuen Peng and Fong Kwong Yam

In general, lighting application, white light emitting diode (LED) usually exposed to an extreme operating temperature of above 90°C. It is well-known that luminous efficacy and…

Abstract

Purpose

In general, lighting application, white light emitting diode (LED) usually exposed to an extreme operating temperature of above 90°C. It is well-known that luminous efficacy and spectral characteristic of white LED are dependent on the temperature, causing thermal effects on luminous efficacy and color shift of white LED become a critical application checkpoint to be addressed by white LED manufactures. Thus, the purpose of this paper is to minimize the thermal stability issue affecting white LED luminescence during operation by introducing phosphor sedimentation process.

Design/methodology/approach

The LED samples were assembled and sent for centrifugation with 0, 5 and 10 revolutions per second (rps), respectively, during phosphor sedimentation process. Luminescence properties of these LED samples were then characterized at a varying temperature to investigate the effect of phosphor sedimentation on the luminescence stability of LED samples. The LED samples were also cross-sectioned and analyzed to understand the phosphor sedimentation mechanism. Computational fluid dynamics (CFD) was applied to study the temperature distribution of the non-phosphor sediment (NPS) and phosphor sediment (PS) LED during operation to validate the hypotheses based on experimental data.

Findings

Experimental results show that the luminous intensity of PS LED samples degrades less significant at high temperature. The experimental results also show that the color coordinate for PS LED samples is more stable and is less blue-shifted than NPS LED samples as the temperature increased. These are because the heat generated by phosphor particles during operation can be dissipated effectively throughout a high thermal conductivity substrate after phosphor sedimentation. Thus, the phosphor temperature of PS LED is lower than NPS LED during operation as validated with the thermal simulation.

Practical implications

The study of this paper is applicable as a reference for industries who intend to resolve the thermal stability of white LED during operation. The luminescence properties changes as a function of the temperature study in this paper can be used to predict the application performances of white LED accurately. Apart from that, the analysis method of temperature distribution using CFD simulations can be extended by other CFD users in the future.

Originality/value

Implementation of phosphor sedimentation to reduce thermal instability issue of white LED has yet to be reported on previous studies. Most literature just studied the thermal instability issue of either assembled LED or raw material, without suggesting any solution to tackle the issue.

Details

Microelectronics International, vol. 37 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 7 March 2016

Yoshio Kobayashi, Tetsuya Ayame, Kyosuke Shibuya, Tomohiko Nakagawa, Yohsuke Kubota, Kohsuke Gonda and Noriaki Ohuchi

This paper aims to propose a simple method for stabilizing silica-coated silver iodide (AgI/SiO2) core-shell particles, of which a colloid solution functions as an X-ray contrast…

Abstract

Purpose

This paper aims to propose a simple method for stabilizing silica-coated silver iodide (AgI/SiO2) core-shell particles, of which a colloid solution functions as an X-ray contrast agent.

Design/methodology/approach

A colloid solution of AgI nanoparticles was prepared by mixing silver perchlorate and potassium iodide in water. The AgI/SiO2 nanoparticles were fabricated by a sol-gel method using NaOH, H2O and tetraethylorthosilicate in ethanol in the presence of AgI nanoparticles surface-modified with 3-mercaptopropyltrimethoxysilane.

Findings

The silica shells of AgI/SiO2 particles were dissolved near the AgI nanoparticle surface, when they were washed by a process composed of centrifugation, removal of supernatant with decantation, addition of water as a washing solution and a shake with a vortex mixer. In contrast, the shells were not damaged by using ethanol as the washing solution, i.e. ethanol-washing. An X-ray photoelectron spectroscopy spectrum of the silica was changed after the ethanol-washing, which indicated that the ethanol-washing had an effect on the chemical bonds in silica. The effect also acted on the silica shells of AgI/SiO2 particles, which did not damage the core-shell structure, i.e. controlled the dissolution of shell.

Originality/value

The paper demonstrates that the ethanol-washing is quite useful for stabilizing the core-shell structure composed of the silica shells.

Details

Pigment & Resin Technology, vol. 45 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 14 November 2012

Norlinda Daud, Robert Shanks and Ing Kong

The effectiveness of centrifugation as the compacting method in preparing high filler composites has been investigated. Different size and shape of fillers were used to ensure…

Abstract

The effectiveness of centrifugation as the compacting method in preparing high filler composites has been investigated. Different size and shape of fillers were used to ensure efficient filler space filling. In situ polymerization of bisphenol-A ethoxy diacrylate after centrifugating produced biomimetic composites with 74-86 % filler content. The filler space was efficiently filled by using a combination of nano and microsize fillers, especially in the nanosilica-CaCO3 composite. The morphology of the composites indicates that the fillers were well dispersed and embedded in the polymer matrix. The etched surface of the nanosilica-talc composite reveals that the combination of talc and nanosilica formed a biomimetic composite that displayed an ordered brick-and-mortar nacre-like structure. The wide-angle X-ray diffraction patterns indicate the crystal structure of CaCO3 and talc were maintained in the composite.

Details

World Journal of Engineering, vol. 9 no. 5
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 April 1977

K.S. ANAND, O.N. ANAND and M.M. SINGH

MODERN heavy‐duty motor oils are almost invariably formulated with detergent‐dispersant type of additives. The types of additive normally employed for this purpose are…

Abstract

MODERN heavy‐duty motor oils are almost invariably formulated with detergent‐dispersant type of additives. The types of additive normally employed for this purpose are organo‐metallic detergent‐dispersants such as metal salts (barium/calcium) of alkyl phenols, petroleum and synthetic sulphonic acids, condensation products of olefins and P2S5, alkyl salicylic acids, etc., on the one hand, and the polymeric ashless types of dispersants such as polymethacrylic esters and N‐substituted long chain alkyl succinimides, on the other. Barium and calcium salts of the petroleum sulphonic acids, however, are by far the most widely used dispersant‐detergent additives. These additives are manufactured from the sodium salts or the sulphonic acids obtained as a by‐product during the sulphonation of mineral oils for the manufacture of white oils and transformer oils. The average molecular weight of the sodium salts is in the range 450—500.

Details

Industrial Lubrication and Tribology, vol. 29 no. 4
Type: Research Article
ISSN: 0036-8792

Article
Publication date: 20 October 2021

Nidhi Goyal, Deepali Rastogi, Manjeet Jassal and Ashwini K. Agrawal

Dyeing and printing are important steps in textile manufacturing. After the process completion, these dyes are released in the effluent. These dyes impart an unacceptable…

Abstract

Purpose

Dyeing and printing are important steps in textile manufacturing. After the process completion, these dyes are released in the effluent. These dyes impart an unacceptable appearance but are also toxic to the soil and water bodies. The present research has been carried out to study the rate of photocatalytic degradation of an azo dye, namely, CI Direct Green 26, using titania nanoparticles under ultra violet (UV) irradiation as a function of temperature and time. Azo dyes account for the majority of all dyestuffs are produced and extensively used in the textile, paper, food, leather, cosmetics and pharmaceutical industries. Titania nanoparticles have been found to successfully degrade these dyes in the presence of UV light. The purpose of the present paper was to study the photodegradation of azo dyes using titania nanoparticles at different temperatures and time periods.

Design/methodology/approach

Titania nanoparticle concentration of 0.1% (w/v) was dispersed in distilled water by sonication for 1 h in sonication bath. The of rate of degradation of Direct Green 26 dye in the titania nanoparticle dispersion, under UV-A exposure was studied at different temperatures ranging from 25°C to 65 °C for time periods ranging from 1 h to 6 h. Photocatalytic degradation tests were performed in a specially designed UV reactor chamber. Raman spectroscopy of Titania nanoparticles, dye and titania/dye mixture before and after UV exposure was carried out using Confocal Laser Dispersion Raman Microscope (Renishaw, UK) with 785 nm excitation laser.

Findings

Titanium dioxide is an efficient photocatalyst for decolourisation of direct dye. The photodegradation of the direct Green dye was found to follow the pseudo first-order reaction. The Arrhenius activation energy was found to be 24.8 kJ/mol with A value of 0.0013 for the photocatalytic degradation of the dye. Raman spectroscopy also confirmed the adsorption of dye on titania nanoparticle and its complete degradation on exposure to UV light.

Practical implications

This research highlights the application of titania nanoparticles for the effective degradation of dye in the effluent from textiles, clothing, paper and any kind of dyeing process. Azo dyes account for the majority of all dyestuffs are produced and extensively used in the textile, paper, food, leather, cosmetics and pharmaceutical industries. Titania nanoparticles have been found to successfully degrade these dyes in the presence of UV light which can be very beneficial for the effluent treatment plants in textile and other industries.

Originality/value

Azo dyes are one of the harmful pollutants released in textile waste water. The degradation and removal of the coloured waste in the textile effluent is an important environmental concern and needs to be investigated. The research is one of the first to investigate and understand the mechanism of the degradation of an azo dye in the presence of titania nanoparticles by Raman spectroscopy.

Details

Research Journal of Textile and Apparel, vol. 26 no. 4
Type: Research Article
ISSN: 1560-6074

Keywords

Article
Publication date: 1 December 2020

Lesia Pavliukh, Sergii Shamanskyi, Sergii Boichenko and Artur Jaworski

This paper aims to evaluate of the microalgae potential for commercial application, in particular to conduct experimental study of biogenic compounds removal from sewage waters by…

Abstract

Purpose

This paper aims to evaluate of the microalgae potential for commercial application, in particular to conduct experimental study of biogenic compounds removal from sewage waters by microalgae, and to calculate economical benefits from biofertizers and biofuel production.

Design/methodology/approach

Experimental study in the concentration change of nitrogen and phosphorus compounds in the cultivation of Chlorella Vulgaris microalgae in various types of sewage water was carried out.

Findings

The efficiency wastewater treatment by microalgae was confirmed. The economic benefit from the biomass utilization as biofuel production was calculated.

Practical implications

Implementation of wastewater treatment technology with biomass recycling for biofuel and biofertilizers production will minimize the impact on the environment.

Originality/value

As a results of experimental studies, the ability of microalgae to reduce biogenic elements in wastewater was confirmed. Microalgae can be used both for wastewater treatment to biogenic elements removal, such as phosphorous and nitrogen compounds, and biofuel, biofertilizers production. Prospects of the commercial use of microalgae are obvious. They are specially adapted to an environment dominated by viscous forces.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 28 September 2010

De‐Xing Peng, Yuan Kang, Shih‐Kang Chen, Fu‐Chun Shu and Yeon‐Pun Chang

The purpose of this paper is to study the dispersion and tribological properties of liquid paraffin with aluminum nanoparticles as additive, which are prepared by the…

Abstract

Purpose

The purpose of this paper is to study the dispersion and tribological properties of liquid paraffin with aluminum nanoparticles as additive, which are prepared by the surface‐modification method using oleic acid (OA).

Design/methodology/approach

The dispersion stability of aluminum nanoparticles in liquid paraffin is measured by spectrophotometry, which can be optimization by Taguchi method. The tribological properties are evaluated by using a ball‐on‐ring wear tester.

Findings

The results show that few concentrations of aluminum nanoparticles as additives in liquid paraffin have better antiwear and antifriction properties than the pure paraffin oil. Scanning electron microscopy and energy dispersive spectrometer analyses can show that the thin films on the rubbing surfaces can be formed by these aluminum nanoparticles, which not only bear the load but also separate the both interfaces, thus the wear and friction can be reduced.

Originality/value

Machine components and mechanism pairs rely on high‐quality lubricants to withstand high temperature and extreme pressure. Extreme pressure and antiwear additives are typically adopted to improve the tribological performance of a fluid lubricant in reducing friction and surface damage under severe conditions.

Details

Industrial Lubrication and Tribology, vol. 62 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 21 April 2023

Majid Monajjemi and Fatemeh Mollaamin

Piperidine side chain-functionalized N, N′-bissalicylidene phenylene di amine di-anion (salphen) consisting of salphen-Zn and salphen-Cu are able to intercalate with nucleic base…

Abstract

Purpose

Piperidine side chain-functionalized N, N′-bissalicylidene phenylene di amine di-anion (salphen) consisting of salphen-Zn and salphen-Cu are able to intercalate with nucleic base stacking of DNA and can be applied as an optical DNA hybridization detector. Attaching DNA and salphen to glass surfaces has been done via coating the surface with the silane coupling agents containing 3-aminopropyltriethoxysilane that was synthesized for acting as a high-affinity RNA carrier matrix. The Schiff base salphen-zinc (II) and salphen-Cu (II) complexes-labelled probe to target nucleic acid renders a colour change of the DNA biosensor to a green and red background colour for zinc and copper, respectively. This study aims to indicate that the DNA biosensor data with high efficiency is used for detection of dengue virus serotypes 2 (DENV-2) and Chikungunya virus (CHIKV) concentration via salphen-Zn (II) and salphen-Cu (II), respectively, in human samples.

Design/methodology/approach

1H-NMR and 13C-NMR have been used via PerkinElmer LAMBDA 35 instrument. The authors also used a double beam spectrophotometer with (CH3)4Si (TMS) as reference and dimethyl sulfoxide as solvent reference in pH = 7.0. Various DNA concentrations have been used for UV spectrophotometry at 300 nm and 400 nm for zinc and copper complexes, respectively. BRUKER mass spectra with DIONEX Ultimate 3000 LC model were used for all measurements. Mettler Teledo model (DSC882e) of differential scanning calorimeter (DSC) was used for measure the melting temperature of metal zinc and copper complexes. The morphology of the silica Nano spheres (SiNs) were scanned by FESEM with Model JSM-6700F from Japan.

Findings

The Cu (II) and Zn (II)-salphen-viruses DNA system for CHIKV and DENV-2, respectively, in different concentration have been investigated via various spectroscopies (Figure 3). CHIKV and DENV-2 DNA were selected from human saliva and urine samples as models for conformations of human G4-DNA. By increasing the amounts of DNAs, and G4, the UV–Vis bands of located above 300 nm, experienced a hypochromic effect. The Cu2+ complex exhibits selectivity towards the G4, and there is a similar affinity for Zn2+ complex binds to the G4. These results collectively suggest that the Cu2+ complex is stronger than the Zn2+ complex. The authors have found copper (II) and zinc (II) compounds and nucleic acid-complexes are strongly fluorescent molecules in the low energy range, from the visible to the near-infrared. Since the fluorescent emission of Zn (II) and Cu (II) complexes are enhanced by the binding to nucleic acids upon visible light exposure when bound to DNA. These complexes are important as selective fluorescent probes for nucleic acids and to highlight their potential application. UV–vis spectroscopy is an accurate for finding the extent of ligand interaction with DNA and metallic complexes–DNA binding. Generally, the binding of intercalative compounds to DNA can be characterized through absorption spectral titrations, where lowering in absorbance (hypochromism) and shift to longer wavelengths (red shift) were observed in this work.

Originality/value

The serum samples have been provided as citrate and collected in tubes after blood is allowed to clot. Then, it has been separated by centrifugation, and the authors have kept serum refrigerated at 4°C or frozen at –20°C. It is notable; specimens have been confirmed by Centres for Disease Control (CDC)-Dengue Branch previously. For the work, these samples have been frozen previously, and the diagnostic practiced tests at the CDC-Dengue Branch have been validated in serum and plasma. Therefore, plasma separated in lavender or heparins are suitable and acceptable for serology testing.

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