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Article
Publication date: 1 April 2024

Ali Hashemi, Parsa Yazdanpanah Qaraei and Mostafa Shabanian-Poodeh

The aim of this paper is to provide a simple yet accurate and efficient geometric method for thermal homogenization of impregnated and non-impregnated coil winding technologies…

Abstract

Purpose

The aim of this paper is to provide a simple yet accurate and efficient geometric method for thermal homogenization of impregnated and non-impregnated coil winding technologies based on the concept of thermal resistance.

Design/methodology/approach

For regular windings, the periodic microscopic cell in the winding space is identified. Also, for irregular windings, the average microscopic cell of the winding is determined. An approximation is used to calculate the thermal resistance of the winding cell. Based on this approximation, the winding insulation is considered as a circular ring around the wire. Mathematical equations are obtained to calculate the equivalent thermal resistance of the cell. The equivalent thermal conductivity of the winding is calculated using equivalent thermal resistance of the cell. Winding thermal homogenization is completed by determining the equivalent thermal properties of the cell.

Findings

The thermal pattern of different windings is simulated and compared with the results of different homogenization methods. The results show that the proposed method is applicable for a wide range of windings in terms of winding scheme, packing factor and winding insulation. Also, the results show that the proposed method is more accurate than other winding homogenization methods in calculating the equivalent thermal conductivity of the winding.

Research limitations/implications

In this paper, the change of electrical resistance of the winding with temperature and thermal contact between the sub-components are ignored. Also, liquid insulators, such as oils, and rectangular wires were not investigated. Research in these topics is considered as future work.

Originality/value

Unlike other homogenization methods, the proposed method can be applied to non-impregnated and irregular windings. Also, compared to other homogenization methods, the proposed method has a simpler formulation that makes it easier to program and implement. All of these indicate the efficiency of the proposed method in the thermal analysis of the winding.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 15 February 2024

Ali Hashemi, Hamed Taheri and Mohammad Dehghani

To prevent the coil from burning or getting damaged, it is necessary to estimate the duration of its operation as long as its temperature does not exceed the permissible limit…

Abstract

Purpose

To prevent the coil from burning or getting damaged, it is necessary to estimate the duration of its operation as long as its temperature does not exceed the permissible limit. This paper aims to investigate the effect of switching on the thermal behavior of impregnated and nonimpregnated windings. Also, the safe operating time for each winding is determined.

Design/methodology/approach

The power loss of the winding is expressed as a function of the winding specifications. Using homogenization techniques, the equivalent thermal properties for the homogenized winding are calculated and used in a proposed thermal equivalent circuit for winding modeling and analysis. The validity and accuracy of the proposed model are determined by comparing its analysis results and simulation and measurement results.

Findings

The results show that copper windings have better thermal behavior and lower temperature compared to aluminum windings. On the other hand, by impregnating or increasing the packing factor of the winding, the thermal behavior is improved. Also, by choosing the right duty cycle for the winding current source, it is possible to prevent the burning or damage of the winding and increase its lifespan. Comparing the measurement results with the analysis results shows that the proposed equivalent circuit has an error of less than 4% in the calculation of the winding center temperature.

Research limitations/implications

In this paper, the effect of temperature on the electrical resistance of the coil is ignored. Also, rectangular wires were not investigated. Research in these topics are considered as future work.

Originality/value

By calculating the thermal time constant of the winding, its safe operation time can be calculated so that its temperature does not exceed the tolerable value (150 °C). The proposed method analyzes both impregnated and nonimpregnated windings with various schemes. It investigates the effects of switching on their thermal behavior. Additionally, it determines the safe operating time for each type of winding.

Details

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

Keywords

Article
Publication date: 6 September 2022

Nader L. Labib, Fouad Zahran, Mohamed Adel Youssef, Azza M. Mazrouaa and Manal Gamal Mohamed

This study aims to extend the pot life without altering the qualities and performance of the coating, which is important to increase when manufacturing polyurethane coatings.

Abstract

Purpose

This study aims to extend the pot life without altering the qualities and performance of the coating, which is important to increase when manufacturing polyurethane coatings.

Design/methodology/approach

An acrylic polyol from a mixture of different monomers of hydroxypropyl methacrylate, methacrylic acid, 2-ethylhexyl acrylate, methyl methacrylate and n-butyl methacrylate was prepared with different ratios of 2,4-pentanedione as a pot life extender. The reaction takes place in presence of di-tert-butyl peroxide as initiator with samples (T1–T7). The physical properties of prepared acrylic polyol were characterized. Then, coating polyurethane varnish was prepared from the prepared acrylic polyol with an aliphatic polyisocyanate in a 1:1 equivalent ratio of OH:NCO at room temperature, in presence of paint thinner (diluents/solvent) and dibutyltin dilaurate as a catalyst to give samples (T1C–T7C). This coating was evaluated via Fourier-transform infrared spectroscopy, drying time, hardness and gloss, distinctness of image and reflected image quality.

Findings

The coating has a prolonged pot life while still maintaining the other qualities, thanks to the greater 2,4-pentanedione content.

Originality/value

It is desired to have a paint which has a satisfactory pot life, short curing time and reduces many drawbacks such as inefficient working and deterioration of the paint before application.

Details

Pigment & Resin Technology, vol. 53 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 25 January 2024

Seda Aygül, Serkan Yılmazsönmez, Arzu Soyalp and Ayse Aytac

Titanium dioxide (TiO2) has high opacity, high brightness and whiteness, owing to its high refractive index value. It is mainly used in the coating industry and continuous efforts…

Abstract

Purpose

Titanium dioxide (TiO2) has high opacity, high brightness and whiteness, owing to its high refractive index value. It is mainly used in the coating industry and continuous efforts have been made to replace some of the TiO2 in paint with new pigments. This study aims to replace part of TiO2 pigment with various percentages of BaSO4, CaCO3 and kaolin in styrene butyl acrylate-based paint formulations, without changing the properties of paints using only titanium dioxide.

Design/methodology/approach

To determine the optimum use rate of new pigment mixing, opacity, gloss, scrub resistance and weather resistance properties have been investigated in the water-based paint formulation. The morphological properties of these samples were examined by scanning electron microscopy analysis.

Findings

In the total color change (ΔE) measurements, it was observed that the sample coded 85Ti/15Ba produced extremely similar results to the situation when TiO2 was used alone. It was seen that the best results were obtained when 85Ti/15Ba was used instead of TiO2.

Originality/value

Comparison research on the impact of replacing TiO2 with BaSO4, CaCO3 and kaolin on the performance characteristics of water-based styrene butyl acrylate-based paint formulations has not been done in the literature, according to the literature search.

Details

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

Keywords

Article
Publication date: 19 May 2022

H. Abd El-Wahab and Raafat A. El-Eisawy

This paper aims to prepare new modified alkyd resins and use it as an antimicrobial binder for surface coating applications.

Abstract

Purpose

This paper aims to prepare new modified alkyd resins and use it as an antimicrobial binder for surface coating applications.

Design/methodology/approach

Various modified alkyd resins were prepared by partial replacement of 3,6-dichloro benzo[b]thiophene-2-carbonyl bis-(2-hydroxy ethyl)-amide as a source of polyol with glycerol and confirmed by acid value, FT-IR, 1H-NMR. The modified alkyd resins were covering a wide range of oil lengths and hydroxyl content (0%, 10%, 20% and 30% excess-OH). The antimicrobial activity of the prepared alkyds was also investigated. The coatings of 60 ± 5 µm thickness were applied to the surface of glass panels and mild steel strips by means of a brush. Physico-mechanical tests, chemical resistance and antimicrobial activities were investigated.

Findings

The obtained results illustrate that the introduction of benzo[b]thiophene derivative as a modifier polyol within the resin structure improved the film performance and enhanced the physico-mechanical characteristics, chemical resistance and the antimicrobial activities.

Practical implications

The modified alkyd resins can be employed as antimicrobial binders in paint compositions for a variety of surfaces, particularly those that are susceptible to a high number of bacteria.

Originality/value

Modified alkyd resins based on antimicrobial heterocyclic compounds have the potential to be promising in the manufacturing of antimicrobial coatings and development of paints, allowing them to function to prevent the spread of microbial infection, which is exactly what the world requires at this time. Also, they can be applied in different substrates for industrial applications.

Details

Pigment & Resin Technology, vol. 52 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 25 April 2023

Ali Hashemi, Parsa Yazdanpanah Qaraei and Mostafa Shabanian

An excessive increase in temperature will reduce the lifespan and even burn the coil. The variety of materials in the structure of the electromagnet along with its multi-layer…

Abstract

Purpose

An excessive increase in temperature will reduce the lifespan and even burn the coil. The variety of materials in the structure of the electromagnet along with its multi-layer winding creates a complex and heterogeneous thermal structure. There are very few researches that are completely focused on the thermal analysis of electromagnets. The purpose of this paper is to provide an accurate, yet fast and simple method for the thermal analysis of cylindrical electromagnets in both transient and steady-state modes. For this purpose, a thermal equivalent circuit (TEC) is presented based on the nodding approach.

Design/methodology/approach

The results of TEC analysis of cylindrical electromagnet, for two orthogonal and orthocyclic winding coil technologies, were compared with the results of the thermal simulation in COMSOL. The authors also built a laboratory model of the cylindrical electromagnet, similar to those analyzed and simulated, and measured the temperature in different parts of it.

Findings

The comparison of the results obtained from different methods for the thermal analysis of the cylindrical electromagnet indicates that the proposed TEC has an error of less than 2%. The simplicity and high accuracy of the results are the most important advantages of the proposed TEC.

Originality/value

Comparing the information and results related to winding schemes, indicates that the orthogonal winding has less cost and weight due to the shorter length of the wire used. On the other hand, orthocyclic winding generates lower temperature and has more lifting force, and is simpler to implement. Therefore, in practice, orthocyclic winding technology is usually used.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 42 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 14 November 2022

Eman Salim

The aim of the present paper to compare the cleaning treatments of paper samples exposed to artificial aging, toluene and isopropyl alcohol gel in cleaning wax stains.

Abstract

Purpose

The aim of the present paper to compare the cleaning treatments of paper samples exposed to artificial aging, toluene and isopropyl alcohol gel in cleaning wax stains.

Design/methodology/approach

In total, paper samples were made from wood pulp. They had a deterioration phenomenon represented in the stains of the paraffin wax, so two types of cleaning were used: A traditional method using a toluene solution and another new method using isopropanol gel by a cotton swap in a circular movement until the completion of the cleaning process. Then, all paper samples were treated with toluene and isopropanol to handle the second artificial aging and detect how the samples were affected by artificial aging. For identifying the efficacy of these materials in removing paraffin wax stains, a range of examinations and analyses were used, such as universal serial bus, scanning electron microscope, infrared analysis (IR), pH analysis, color change analysis. Moreover, these results were compared with the standard sample’s results.

Findings

The results of examinations and analyses proved that the use of toluene affected the paper samples. Their effects were twice as weak, fragile and degraded paper fibers compared to isopropanol gel. Therefore, the isopropanol gel is preferred for paper cleaning to the toluene solution.

Originality/value

This paper highlights the efficiency of isopropyl alcohol gel in cleaning wax stains from historical paper supports.

Details

Pigment & Resin Technology, vol. 52 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 25 March 2024

Mostafa Abdel-Hamied, Ahmed A.M. Abdelhafez and Gomaa Abdel-Maksoud

This study aims to focus on the main materials used in consolidation processes of illuminated paper manuscripts and leather binding.

Abstract

Purpose

This study aims to focus on the main materials used in consolidation processes of illuminated paper manuscripts and leather binding.

Design/methodology/approach

For each material, chemical structure, chemical composition, molecular formula, solubility, advantages, disadvantages and its role in treatment process are presented.

Findings

This study concluded that carboxy methyl cellulose, hydroxy propyl cellulose, methyl cellulose, cellulose acetate, nanocrystalline cellulose, funori, sturgeon glue, poly vinyl alcohol, chitosan, chitosan nanoparticles (NPs), gelatin, aquazol, paraloid B72 and hydroxyapatite NPs were the most common and important materials used for the consolidation of illuminated paper manuscripts. For the leather bindings, hydroxy propyl cellulose, polyethylene glycol, oligomeric melamine-formaldehyde resin, acrylic wax SC6000, pliantex, paraloid B67 and B72, silicone oil and collagen NPs are the most consolidants used.

Originality/value

Illuminated paper manuscripts with leather binding are considered one of the most important objects in libraries, museums and storehouses. The uncontrolled conditions and other deterioration factors inside the libraries and storehouses lead to degradation of these artifacts. The brittleness, fragility and weakness are considered the most common deterioration aspects of illuminated paper manuscripts and leather binding. Therefore, the consolidation process became vital and important to solve this problem. This study presents the main materials used for consolidation process of illuminated paper manuscripts and leather bindings.

Details

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

Keywords

Article
Publication date: 16 January 2024

Amin Reihani, Fatemeh Shaki and Ala Azari

Acrylamide (AA) is predominantly used as a synthetic substance within various industries. However, AA is also recognized as a carcinogen. Zinc oxide nanoparticles (ZnO-NPs) are…

Abstract

Purpose

Acrylamide (AA) is predominantly used as a synthetic substance within various industries. However, AA is also recognized as a carcinogen. Zinc oxide nanoparticles (ZnO-NPs) are becoming increasingly attractive as medical agents. However, to the knowledge, the effects of ZnO-NPs on preventing cytotoxicity with AA have not been reported. Therefore, this study aims to determine the protective effects of ZnO-NPs against the cytotoxicity caused by AA.

Design/methodology/approach

MTT assay was used to determine the cytotoxicity. Reactive oxygen species (ROS) formation, carbonyl protein, malondialdehyde (MDA) and glutathione (GSH) were measured and analyzed statistically.

Findings

The findings observed that the presence of 200 µM AA led to a substantial reduction in cell viability (p < 0.001). However, ZnO-NPs restored cell viability at 50 and 100 µM concentrations (p = 0.0121 and p = 0.0011, respectively). The levels of ROS were significantly reduced (p = 0.001 and p = < 0.001) to 518 ± 47.57 and 364 ± 47.79, respectively, compared to the AA group. The levels of GSH were significantly increased (p = 0.004 and p = 0.002) to 16.9 ± 1.3 and 17.6 ± 0.5, respectively, compared to the AA group. The levels of MDA were significantly decreased (p = 0.005, p < 0.001 and p < 0.001) when compared to the AA group, as were the levels of carbonyl protein (p = 0.009 and p < 0.002) in comparison to the AA group.

Originality/value

In summary, the outcomes of this research indicate that ZnO-NPs played a role in inhibiting AA-induced oxidative stress and cytotoxicity.

Details

Nutrition & Food Science , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0034-6659

Keywords

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