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1 – 10 of over 4000Watcharaporn Wongsakoonkan, Sumate Pengpumkiat, Vorakamol Boonyayothin, Chaiyanun Tangtong, Wisanti Laohaudomchok and Wantanee Phanprasit
The purpose of this study was to develop an accurate, selective, low-cost and user-friendly colorimetric pad to detect formaldehyde at low concentration.
Abstract
Purpose
The purpose of this study was to develop an accurate, selective, low-cost and user-friendly colorimetric pad to detect formaldehyde at low concentration.
Design/methodology/approach
1-phenyl-1,3-butanedione, a reactive chemical, was selected to develop the colorimetric pad for indoor air formaldehyde measurement. Silica nanoparticle impregnated with the reactive chemical was coated on the cellulose filter surface to increase the reactive site. A certified formaldehyde permeation tube was used to generate six varied concentrations between 0.01 and 0.10 ppm in a test chamber. The color intensity on the pads was measured using an image processing program to produce a formaldehyde concentration reading chart. The colorimetric pad was tested for optimum reaction time, accuracy, precision, stability, selectivity and shelf life.
Findings
The color of the pads changed from white to yellow and the color intensity varied with the concentrations and appeared to be stable after exposure to formaldehyde for 8 hours. At room temperature, the stability of the pad was 7 days, and shelf life was 120 days. The accuracy, precision and bias of the pad were 12.38%, 0.032 and 6.0%, respectively. Carbonyl compounds, benzene and toluene did not interfere with the reading of this developed colorimetric pad.
Originality/value
The developed colorimetric pad meets NIOSH's criteria for an overall accuracy of ±25%, bias = 10%. They were accurate at low concentrations, user-friendly and had low cost compared to an electronic direct reading instrument (cost of chemicals and materials was 21.50 Bath or 0.69 USD per piece) so that favorable for the use of general people for health protection.
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Aiqin Gao, Hongjuan Zhang and Kongliang Xie
– The purpose of this paper is to synthesise a tetrakisazo reactive dye and to characterise its dyeing property to meet the demand for better black reactive dyes.
Abstract
Purpose
The purpose of this paper is to synthesise a tetrakisazo reactive dye and to characterise its dyeing property to meet the demand for better black reactive dyes.
Design/methodology/approach
The novel tetrakisazo navy-blue reactive dye based on 4,4′-diaminostilbene-2,2′-disulphonic acid was designed and synthesized. The dyeing behaviour of it on cotton fabric was discussed. The synergistic blackening effect and absorbance spectra were investigated by absorbance and reflectance spectra, K/S and colorimetric data.
Findings
The exhaustion and fixation of the designed reactive dye were higher than 20 per cent than those of the commercial reactive dye, CI Reactive Black 5. The novel reactive dye has complementary with Reactive Red SPB and Reactive Yellow C-5R in absorbance spectra from 360 to 700 nm. Three reactive dyes had synergistic effect in colour deepening properties. The dyed cotton fabric possessed high K/S value and low reflectance in the whole visual spectrum range from 360 to 700 nm.
Practical implications
Comparison with the commercial Reactive Black DN-RN, the blackness of the dyed fabrics with the mixture dyes was greatly improved and the fastness properties on cotton fabrics were also good.
Originality/value
The paper is an original research work. Because the mixture dyes had better blackness and good fastness properties, it would have wide application in the dyeing of cotton fabric.
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Chongbin Zhao, B.E. Hobbs, H.B. Mühlhaus, A. Ord and Ge Lin
Numerical methods are used to solve double diffusion driven reactive flow transport problems in deformable fluid‐saturated porous media. In particular, the temperature dependent…
Abstract
Numerical methods are used to solve double diffusion driven reactive flow transport problems in deformable fluid‐saturated porous media. In particular, the temperature dependent reaction rate in the non‐equilibrium chemical reactions is considered. A general numerical solution method, which is a combination of the finite difference method in FLAC and the finite element method in FIDAP, to solve the fully coupled problem involving material deformation, pore‐fluid flow, heat transfer and species transport/chemical reactions in deformable fluid‐saturated porous media has been developed. The coupled problem is divided into two sub‐problems which are solved interactively until the convergence requirement is met. Owing to the approximate nature of the numerical method, it is essential to justify the numerical solutions through some kind of theoretical analysis. This has been highlighted in this paper. The related numerical results, which are justified by the theoretical analysis, have demonstrated that the proposed solution method is useful for and applicable to a wide range of fully coupled problems in the field of science and engineering.
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Hongmei Liu and Tat Leung Chan
The purpose of this paper is to study the evolution and growth of aerosol particles in a turbulent planar jet by using the newly developed large eddy simulation…
Abstract
Purpose
The purpose of this paper is to study the evolution and growth of aerosol particles in a turbulent planar jet by using the newly developed large eddy simulation (LES)-differentially weighted operator splitting Monte Carlo (DWOSMC) method.
Design/methodology/approach
The DWOSMC method is coupled with LES for the numerical simulation of aerosol dynamics in turbulent flows.
Findings
Firstly, the newly developed and coupled LES-DWOSMC method is verified by the results obtained from a direct numerical simulation-sectional method (DNS-SM) for coagulation occurring in a turbulent planar jet from available literature. Then, the effects of jet temperature and Reynolds number on the evolution of time-averaged mean particle diameter, normalized particle number concentration and particle size distributions (PSDs) are studied numerically on both coagulation and condensation processes. The jet temperature and Reynolds number are shown to be two important parameters that can be used to control the evolution and pattern of PSD in an aerosol reactor.
Originality/value
The coupling between the Monte Carlo method and turbulent flow still encounters many technical difficulties. In addition, the relationship between turbulence, particle properties and collision kernels of aerosol dynamics is not yet well understood due to the theoretical limitations and experimental difficulties. In the present study, the developed and coupled LES-DWOSMC method is capable of solving the aerosol dynamics in turbulent flows.
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C.W.M. Yuen, S.K.A. Ku, P.S.R. Choi, C.W. Kan and S.Y. Tsang
An infrared (IR) spectroscopic technique was used to determine the possible functional groups and chemical compounds present in commercially available ink-jet printing reactive…
Abstract
An infrared (IR) spectroscopic technique was used to determine the possible functional groups and chemical compounds present in commercially available ink-jet printing reactive dyes of four primary colours, i.e. Cyan, Magenta, Yellow, and Black. Although other instrumental analytical methods can help to determine the actual chemical composition of reactive dyes, the IR technique alone can still provide important structural information about the commercially available reactive dyes. Experimental results revealed that the reactive dyes under determination contained the same functional groups and chemical compounds as the reference reactive dyes.
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Md Asadul Hoque, Md Saiduzzaman, A. Nayeem Faruqui and Md Ashadul Islam
This paper aims to examine the loss of tenacity and colorfastness properties of bleached and modified (acrylonitrile, AN and methacrylonitrile, MAN) jute fibres dyed with Reactive…
Abstract
Purpose
This paper aims to examine the loss of tenacity and colorfastness properties of bleached and modified (acrylonitrile, AN and methacrylonitrile, MAN) jute fibres dyed with Reactive Orange 14 and Basic Violet 14.
Design/methodology/approach
Jute fibres dyed with Reactive Orange 14 and Basic Violet 14 were studied as a function of exposure to sunlight in air, washing with soap solution and spotting with acids and alkalis.
Findings
Dye absorption of Basic Violet 14 was higher compared to Reactive Orange 14 at optimum dyeing conditions. Optimum dye uptake of Reactive Orange 14 required relatively severe conditions compared to that of Basic Violet 14. Whereas, Reactive Orange 14 showed overall good colorfastness to sunlight and moderate in washing compared to Basic Violet 14. All the bleached and modified fibres showed good colorfastness to weak acids and alkalis regardless of Reactive Orange 14 and Basic Violet 14 dyes. The loss in tenacity was higher in the case of non-modified fibres, and among the modified fibres, Basic Violet 14 showed the lowest loss in tenacity in the exposure to sunlight.
Originality/value
Many studies have been devoted to improve the substantivity of cellulosic fibre for reactive dyes. A few efforts were made to improve the light fastness. In this work, investigation will be made on a comparative study of loss of tenacity and colorfastness properties of bleached and modified (AN and MAN) jute fibres dyed with both Reactive Orange 14 and Basic Violet 14 on exposure to sunlight, washing and acid and alkali spotting. Optimum dyeing conditions will also be investigated for economic dyeing.
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Pundalik Pandharinath Mali, Nilesh S. Pawar, Narendra S. Sonawane, Vikas Patil and Rahul Patil
The purpose of this work was to develop a new trispiperazido phosphate-based reactive diluent (diphosphate-piperazine hydroxyl acrylate [DPHA]) and used as a flame retardant with…
Abstract
Purpose
The purpose of this work was to develop a new trispiperazido phosphate-based reactive diluent (diphosphate-piperazine hydroxyl acrylate [DPHA]) and used as a flame retardant with an epoxy acrylate (EA) in ultraviolet (UV)-curable wood coating.
Design/methodology/approach
The concentration of reactive diluent was varied from 0% to 20% in the UV-curable formulation with constant photoinitiator concentration. The effect of DPHA concentration on film properties was studied by differential scanning calorimetry and thermogravimetric analysis, gel content, water absorption and limiting oxygen index.
Findings
The results showed that the viscosity of the prepared formulation decreased by increasing reactive diluent (DPHA) concentration which leads to improving the coating efficiency. A high concentration of reactive diluent (DPHA) of the cured films shows good resistance against stain, mechanical and thermal properties, which results in an increased glass transition temperature (Tg) and cross-linking density of the films.
Originality/value
The new trispiperazido phosphate-based reactive diluent was used in wood coating formulation, which resulted in excellent flame-retardant properties with higher cross-linked density with good stain resistance. This material can provide a wide range of application for coating industries to produce a glossy finish.
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Abstract
Nanostructured reactive foils have attracted a great deal of interest recently due to their unique mechanical and thermal properties. Reactive thin foil can be used as a controllable, localized heating source for joining applications, which enable soldering and brazing of materials at room temperature. In this paper, multiphysics-based numerical simulations were performed to simulate reactive thin foils. The conductive heat transfer equation and mass diffusion equations were solved for 1D, 2D, and 3D cases. 1D simulation examined the effect of the chemical reaction rate on the flame speed; 2D simulation gave the detailed temperature and composition distribution in the bi-layers; and 3D simulation demonstrated the localized heating effect of reactive thin foils on a silicon wafer substrate.
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N.S.E. Ahmed, R.M. El‐Shishtawy and M.M. Kamel
To explore the use of power ultrasound as an environmentally friendly heating technology for the pre‐treatment of linen fibres with sodium perborate as the halogen free oxidising…
Abstract
Purpose
To explore the use of power ultrasound as an environmentally friendly heating technology for the pre‐treatment of linen fibres with sodium perborate as the halogen free oxidising agent and to study the impact of this process on its dyeability with reactive dyes.
Design/methodology/approach
Exploiting power ultrasound in the wet processes of linen fibres was made in two steps, i.e. ultrasonic pre‐treatment with sodium perborate followed by ultrasonic dyeing with reactive dyes. Therefore, comparative studies between conventional and ultrasonic techniques as well as the different factors that may affect these processes were investigated. The effect of the pre‐treatment on fibre fine structure using X‐ray diffraction technique was also investigated.
Findings
The results of the increase of whiteness index indicate that ultrasonic pre‐treatment was better at all studied treatment times and at low temperature. X‐ray diffraction studies on blank, ultrasonically and conventionally pre‐treated linen fibres have shown 70.41, 67.51 and 64.90 per cent crystallinity, respectively. The dyeing of the pre‐treated fibres with Reactive Red 24 was simultaneously carried out under both ultrasonic and conventional heating conditions to study the effect of dye concentrations at different dyeing temperatures. The colour strength values obtained for the dyed samples using ultrasonic at 50°C were slightly higher than those obtained using conventional heating at 80°C. Ultrasonic enhancement in the pre‐treatment and dyeing in terms of the percent increase of colour strength of the dyed fabric was estimated to be 157.94 per cent higher than that of conventional heating method. The results of wet fastness properties of the dyed fibres using ultrasonic revealed improvement relative to those obtained using conventional heating method.
Research limitations/implications
The improved wet processes of linen fibres suggest further investigation to exploit power ultrasound in the wet processes of cellulosic fibres at low temperature using different classes of halogen free bleaching agents and dyeing with different classes of heat‐requiring reactive dyes. Also, this work may inspire the synthesis of new generation of heat‐requiring reactive dyes.
Practical implications
The work presented has significant potential industrial application for cleaner production in textile industries.
Originality/value
The present study of linen pre‐treatment with non‐toxic total chlorine free oxidising agent and its dyeability with reactive dyes using power ultrasound is novel and could be used in the wet processes of linen fibres.
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Pooneh Kardar, Morteza Ebrahimi and Saeed Bastani
The purpose of this work was to study the effect of chemical structure of reactive diluents on the curing behaviour and physical–mechanical properties of a titanium dioxide…
Abstract
Purpose
The purpose of this work was to study the effect of chemical structure of reactive diluents on the curing behaviour and physical–mechanical properties of a titanium dioxide pigmented UV-curable epoxy acrylate system.
Design/methodology/approach
Two different tri-functional and two different tetra-functional acrylate monomers were used as reactive diluents in the formulations. The curing behaviour of the formulations was studied by using photo-differential scanning calorimetry analysis. The rate of curing, conversion at the maximum rate and ultimate conversion for different formulations were calculated. In addition, the physical and mechanical characteristics of the cured films, including glass transition temperature and modulus, were measured by using a dynamic mechanical analysis technique.
Findings
The results showed that the ultimate conversion for non-pigmented pentaerythritol triacrylate (PETA) and trimethylol propane triacrylate (TMPTA) formulations were almost similar, but the interference effect of titanium dioxide particles on the curing of the PETA formulations was found to be more considerable in comparison to the TMPTA formulations. The extent of reaction for tetra-functional acrylate monomers was considerably less than those for tri-functional acrylate monomers. The Tg and storage modulus of non-pigmented PETA, TMPTA and pentaerythritol tetraacrylate (PE4TA) formulations were almost the same and higher than that for ditrimethylol propane tetraacrylate (DiTMP4TA) formulations. However, Tg and storage modulus of pigmented tetra-functional acrylate monomer formulations were higher than those for tri-acrylate monomer formulations.
Research limitations/implications
The curing conditions (temperature and UV intensity) can affect the network formation and consequently will affect on the properties of the cured films.
Practical implications
The pigmented UV-curable coatings are interested for many industries such as wood and automotive industries. The reported data can be used by the formulators working in the R&D departments. In addition, the results obtained can be used by the researchers who are active in the field of structure–property relationship for UV-curable coatings.
Social implications
UV-curing systems are considered as one of the most environment-friendly coatings system. Therefore, the developing of its knowledge can help to extend its usage to different applications.
Originality/value
The photopolymerisation of pigmented coatings is a great challenge and is hardly investigated in the literature. Therefore, in this research, the effect of chemical structure and functionality of different multifunctional acrylate monomers on the curing behaviour of pigmented formulations was investigated.
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