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1 – 10 of 148
Open Access
Article
Publication date: 6 September 2022

Agnieszka Chmielewska, Bartlomiej Adam Wysocki, Elżbieta Gadalińska, Eric MacDonald, Bogusława Adamczyk-Cieślak, David Dean and Wojciech Świeszkowski

The purpose of this paper is to investigate the effect of remelting each layer on the homogeneity of nickel-titanium (NiTi) parts fabricated from elemental nickel and titanium…

1256

Abstract

Purpose

The purpose of this paper is to investigate the effect of remelting each layer on the homogeneity of nickel-titanium (NiTi) parts fabricated from elemental nickel and titanium powders using laser powder bed fusion (LPBF). In addition, the influence of manufacturing parameters and different melting strategies, including multiple cycles of remelting, on printability and macro defects, such as pore and crack formation, have been investigated.

Design/methodology/approach

An LPBF process was used to manufacture NiTi alloy from elementally blended powders and was evaluated with the use of a remelting scanning strategy to improve the homogeneity of fabricated specimens. Furthermore, both single melt and up to two remeltings were used.

Findings

The results indicate that remelting can be beneficial for density improvement as well as chemical and phase composition homogenization. Backscattered electron mode in scanning electron microscope showed a reduction in the presence of unmixed Ni and Ti elemental powders in response to increasing the number of remelts. The microhardness values of NiTi parts for the different numbers of melts studied were similar and ranged from 487 to 495 HV. Nevertheless, it was observed that measurement error decreases as the number of remelts increases, suggesting an increase in chemical and phase composition homogeneity. However, X-ray diffraction analysis revealed the presence of multiple phases regardless of the number of melt runs.

Originality/value

For the first time, to the best of the authors’ knowledge, elementally blended NiTi powders were fabricated via LPBF using remelting scanning strategies.

Open Access
Article
Publication date: 17 December 2018

Khavhatondwi Rinah Netshiheni, Mpho Edward Mashau and Afam Israel Obiefuna Jideani

White maize-based porridge is a staple food for about 80 per cent consumers in South Africa and in other sub-Saharan African countries contributing significantly to the diet of…

4971

Abstract

Purpose

White maize-based porridge is a staple food for about 80 per cent consumers in South Africa and in other sub-Saharan African countries contributing significantly to the diet of rural population in developing countries. White maize is deficient in some amino acids and over-dependency on its porridge may lead to high prevalence of malnutrition-related health conditions. Moringa oleifera (MO) and termite (Macrotermes falciger) are known to contain substantial amount of protein. The purpose of this study was to determine the effect of powders from MO leaves and termite on the nutritional and sensory properties of instant maize porridge.

Design/methodology/approach

Inclusion of MO and termite powder in instant maize porridge, using different treatments were considered using a completely randomised design. Factor levels were control (maize flour) cooked, blanched and uncooked MO samples. Data were analysed using SPSS version 23.

Findings

Protein content of fortified instant maize porridge (FMP) significantly increased from 10.0 to 21.2 per cent compared to unfortified porridge, and this could be attributed to the substitution effect, as fresh uncooked MO leaves are reported to be high in protein. Mineral content of FMP was higher in zinc, iron, calcium and magnesium. Calcium values of FMP were higher (276.8 mg/100 g) compared to unfortified porridge (7.1 mg/100 g). Upon the addition of MO leaves and termite powder, the zinc content increased from 3.4 mg/100to 7.6 mg/100 g. Higher iron values (27.9-36.9 mg/100 g) were observed among fortified samples. The sensory result showed that control sample had higher acceptance than the fortified samples (p = 0.02). Sensory analysis showed that among fortified porridges, blanched sample was rated high for colour and texture, cooked sample was higher in taste and uncooked sample was higher for aroma. Control sample had higher acceptance than fortified porridges for taste. The results of this study showed that the addition of MO leaves and termite powder to instant maize porridge has led to a substantial increase in the nutritional value of FMP.

Originality/value

This study was carried out to develop instant maize porridge fortified with MO leaves and termite powder suitable for infants, pregnant mothers and other maize consumers. The author aimed at improving the nutritional content of instant maize porridge by combining it with MO leaves and termite powders. The results showed that the addition of MO leaves and termite powders to instant maize porridge has led to a substantial increase in the nutritional value of FMP. Therefore, powder from MO leaves and termites could be used in complementary foods to increase protein and mineral contents.

Details

Nutrition & Food Science, vol. 49 no. 4
Type: Research Article
ISSN: 0034-6659

Keywords

Content available
Article
Publication date: 1 August 2000

55

Abstract

Details

Pigment & Resin Technology, vol. 29 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

Content available
Article
Publication date: 1 December 2001

62

Abstract

Details

Industrial Lubrication and Tribology, vol. 53 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Content available
Article
Publication date: 1 June 1999

110

Abstract

Details

Pigment & Resin Technology, vol. 28 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Content available
Article
Publication date: 26 June 2009

100

Abstract

Details

Anti-Corrosion Methods and Materials, vol. 56 no. 4
Type: Research Article
ISSN: 0003-5599

Content available
Article
Publication date: 1 August 2003

Brian Ellis

35

Abstract

Details

Microelectronics International, vol. 20 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Open Access
Article
Publication date: 29 February 2024

Guanchen Liu, Dongdong Xu, Zifu Shen, Hongjie Xu and Liang Ding

As an advanced manufacturing method, additive manufacturing (AM) technology provides new possibilities for efficient production and design of parts. However, with the continuous…

Abstract

Purpose

As an advanced manufacturing method, additive manufacturing (AM) technology provides new possibilities for efficient production and design of parts. However, with the continuous expansion of the application of AM materials, subtractive processing has become one of the necessary steps to improve the accuracy and performance of parts. In this paper, the processing process of AM materials is discussed in depth, and the surface integrity problem caused by it is discussed.

Design/methodology/approach

Firstly, we listed and analyzed the characterization parameters of metal surface integrity and its influence on the performance of parts and then introduced the application of integrated processing of metal adding and subtracting materials and the influence of different processing forms on the surface integrity of parts. The surface of the trial-cut material is detected and analyzed, and the surface of the integrated processing of adding and subtracting materials is compared with that of the pure processing of reducing materials, so that the corresponding conclusions are obtained.

Findings

In this process, we also found some surface integrity problems, such as knife marks, residual stress and thermal effects. These problems may have a potential negative impact on the performance of the final parts. In processing, we can try to use other integrated processing technologies of adding and subtracting materials, try to combine various integrated processing technologies of adding and subtracting materials, or consider exploring more efficient AM technology to improve processing efficiency. We can also consider adopting production process optimization measures to reduce the processing cost of adding and subtracting materials.

Originality/value

With the gradual improvement of the requirements for the surface quality of parts in the production process and the in-depth implementation of sustainable manufacturing, the demand for integrated processing of metal addition and subtraction materials is likely to continue to grow in the future. By deeply understanding and studying the problems of material reduction and surface integrity of AM materials, we can better meet the challenges in the manufacturing process and improve the quality and performance of parts. This research is very important for promoting the development of manufacturing technology and achieving success in practical application.

Details

Journal of Intelligent Manufacturing and Special Equipment, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2633-6596

Keywords

Open Access
Article
Publication date: 9 February 2024

Martin Novák, Berenika Hausnerova, Vladimir Pata and Daniel Sanetrnik

This study aims to enhance merging of additive manufacturing (AM) techniques with powder injection molding (PIM). In this way, the prototypes could be 3D-printed and mass…

Abstract

Purpose

This study aims to enhance merging of additive manufacturing (AM) techniques with powder injection molding (PIM). In this way, the prototypes could be 3D-printed and mass production implemented using PIM. Thus, the surface properties and mechanical performance of parts produced using powder/polymer binder feedstocks [material extrusion (MEX) and PIM] were investigated and compared with powder manufacturing based on direct metal laser sintering (DMLS).

Design/methodology/approach

PIM parts were manufactured from 17-4PH stainless steel PIM-quality powder and powder intended for powder bed fusion compounded with a recently developed environmentally benign binder. Rheological data obtained at the relevant temperatures were used to set up the process parameters of injection molding. The tensile and yield strengths as well as the strain at break were determined for PIM sintered parts and compared to those produced using MEX and DMLS. Surface properties were evaluated through a 3D scanner and analyzed with advanced statistical tools.

Findings

Advanced statistical analyses of the surface properties showed the proximity between the surfaces created via PIM and MEX. The tensile and yield strengths, as well as the strain at break, suggested that DMLS provides sintered samples with the highest strength and ductility; however, PIM parts made from environmentally benign feedstock may successfully compete with this manufacturing route.

Originality/value

This study addresses the issues connected to the merging of two environmentally efficient processing routes. The literature survey included has shown that there is so far no study comparing AM and PIM techniques systematically on the fixed part shape and dimensions using advanced statistical tools to derive the proximity of the investigated processing routes.

Open Access
Article
Publication date: 28 January 2022

Kiranmai Uppuluri and Dorota Szwagierczak

The purpose of this work was to characterize NiMn2O4 spinel-based thermistor powder, to use it in screen printing technology to fabricate temperature sensors, to study their…

1034

Abstract

Purpose

The purpose of this work was to characterize NiMn2O4 spinel-based thermistor powder, to use it in screen printing technology to fabricate temperature sensors, to study their performance for different sintering temperatures of thermistor layer, with and without insulative cover, as well as to investigate stability of the fabricated thermistors and their applicability in water quality monitoring.

Design/methodology/approach

After the characterization of starting NiMn2O4 spinel-based thermistor powder, it was converted to thick film paste which was screen printed on alumina substrate. Thermistor layers were sintered at four different sintering temperatures: 980°C, 1050°C, 1150°C and 1290°C. An interdigitated pattern of Ag-Pd conductive layer was used to reduce the resistance. Temperature-resistance characteristics were investigated in air and water, with and without insulative cover atop the thermistor layer. Stability of the fabricated thermistors after aging at 120°C for 300 h was also examined.

Findings

Thick film NiMn2O4 spinel thermistors, prepared by screen printing and sintering in the temperature range 980°C–1290°C, exhibited good negative temperature coefficient (NTC) characteristics in the temperature range −30°C to 145°C, including high temperature coefficient of resistance, good stability and applicability in water.

Originality/value

This study explores the range of sintering temperature that can be applied for NiMn2O4 thermistor thick films without compromising on the temperature sensing performance in air and water, as well as stability of the thermistors after aging at elevated temperatures.

Details

Sensor Review, vol. 42 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

1 – 10 of 148