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Article
Publication date: 1 April 1995

J.H. Choi

Photoresist imaging traditionally uses silver halide or diazo based phototools for contact exposure to an actinic UV light source. By contrast, laser direct imaging uses…

Abstract

Photoresist imaging traditionally uses silver halide or diazo based phototools for contact exposure to an actinic UV light source. By contrast, laser direct imaging uses digital imaging data to control a laser beam scanner to write directly on to the photoresist, therefore eliminating the need for phototools. In the past, even though the benefit of a UV system was recognised, laser direct imaging was mainly limited to the use of a visible laser as early UV lasers were low in power, unreliable and expensive. So far, no visible systems have gained commercial recognition because of the inherent deficiencies of the visible system. Recent advantages in UV laser equipment and UV sensitive photoresist have now made UV laser direct imaging a viable alternative to traditional contact imaging. As new UV laser imaging systems start to emerge, interest and attention are also growing among printed circuit board manufacturers. This paper discusses various attributes of a UV laser direct imaging system and fundamental differences in photophysics between laser direct imaging and conventional UV imaging.

Details

Circuit World, vol. 21 no. 4
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 23 March 2022

Muneeb Ahmad Malik, Yasmeena Jan, Afrozul Haq, Jasmeet Kaur and Bibhu Prasad Panda

The purpose of this study was to optimize the parameters for enhancing the vitamin D2 formation in three edible mushroom varieties, namely, shiitake mushroom (Lentinula

Abstract

Purpose

The purpose of this study was to optimize the parameters for enhancing the vitamin D2 formation in three edible mushroom varieties, namely, shiitake mushroom (Lentinula edodes), white button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus) using ultraviolet (UV) irradiation.

Design/methodology/approach

Freshly harvested mushrooms were irradiated with UV-B and UV-C lamps. Further, mushrooms were treated with UV-B at a distance ranging between 10 and 50 cm from the UV light source, for 15–150 min, to maximize the conversion of ergosterol to vitamin D2. Analysis of vitamin D2 content in mushrooms before and after UV exposure was done by high pressure liquid chromatography (HPLC).

Findings

HPLC results showed a significant (p < 0.001) increase in vitamin D2 levels of shiitake (17.3 ± 0.35 µg/g), button (24.9 ± 0.71 µg/g) and oyster (19.1 ± 0.35 µg/g) mushrooms, irradiated with UV-B at a distance of 20–30 cm for 120 min. Further, stability studies revealed that vitamin D2 levels in UV-B-irradiated mushrooms gradually increased for 48 and 72 h of storage at room and refrigeration temperatures, respectively. During cooking operations, 62%–93% of vitamin D2 was retained in UV-B-irradiated mushrooms.

Originality/value

This study describes the most effective parameters such as ideal wavelength, mushrooms size, duration of exposure and distance from UV sources for maximum vitamin D2 formation in edible mushrooms using UV irradiation. Further, assessment of vitamin D2 stability in UV exposed mushrooms during storage period and cooking operations has been carried out. In addition, this study also provides a comparison of the vitamin D2 levels of the three widely cultivated and consumed mushroom varieties treated simultaneously under similar UV exposure conditions.

Details

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

Keywords

Article
Publication date: 28 May 2021

Anand Dixit, Kunal Wazarkar and Anagha S. Sabnis

Epoxy acrylate which is commercially utilized for UV curable coatings although has excellent adhesion, flexibility, hardness and chemical resistance, they lack in…

Abstract

Purpose

Epoxy acrylate which is commercially utilized for UV curable coatings although has excellent adhesion, flexibility, hardness and chemical resistance, they lack in antimicrobial properties. Citric acid (CA) is economical as well as a bio-based compound which possess an antimicrobial activity. So, the purpose of this research investigation is the preparation of CA-based oligomer which can be further incorporated with epoxy acrylate and tri (propylene glycol) Diacrylate (TPGDA) to form uv curable coating and the study of its antimicrobial property.

Design/methodology/approach

A UV-curable unsaturated oligomer (CUV) was synthesized from CA and glycidyl methacrylate (GMA). The chemical structure of CUV was confirmed by FTIR, 1H NMR, GPC, hydroxyl value, acid value and iodine value. Further, CUV was assimilated as an antimicrobial as well as crosslinking agent to copolymerize with epoxy acrylate oligomer and a series of UV-cured antimicrobial coatings were concocted by employing UV-curing machine. The consequence of varying the fraction of CUV on the mechanical, chemical, thermal and antimicrobial properties of UV-cured wood coatings was explored.

Findings

Results exhibited good mechanical, chemical and thermal properties. In addition, it was perceived that the zone of inhibition against S. aureus got enlarged with increasing content of CUV in the coating formulation.

Originality/value

The synthesized bio-based CUV reveals an extensive potential to ameliorate the antimicrobial properties of UV-curable coatings.

Details

Pigment & Resin Technology, vol. 50 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 8 November 2011

Nishant Bhore and Prakash Mahanwar

The purpose of this paper is to synthesise UV curable emulsion latex and to study characteristics and various performance properties such as tackiness, peel adhesion and…

Abstract

Purpose

The purpose of this paper is to synthesise UV curable emulsion latex and to study characteristics and various performance properties such as tackiness, peel adhesion and cohesive strength for pressure sensitive adhesive (PSA) application after UV curing.

Design/methodology/approach

The two component water‐based ultraviolet (UV) curable acrylate PSAs were synthesised by emulsion copolymerization. The synthesised emulsion samples were characterised and various performance properties such as tackiness, peel adhesion and cohesive strength for PSAs were tested after UV curing.

Findings

The thermal analysis showed the effect of methyl methacrylate (MMA) content on the glass transition temperature of emulsions, which had significant effect on tack. Effects of varying concentration of multifunctional monomer trimethylolpropane triacrylate (TMPTA) and UV exposure time on properties of UV curable PSA were also studied.

Research limitations/implications

The results associated with the UV curable water based PSA has certain advantages, such as low VOC and fast curing rate and with the scope for further research by using the radiations with different intensities or other radiation systems such as electron beam curing.

Practical implications

Practically the UV water based PSAs are already in industrial use for glass lamination, silicon semiconductor dicing, and in medical use for band aids and drug delivery systems and for dental applications for cavity filling.

Originality/value

The water based UV curable PSA synthesised by emulsion polymerization had very good tackiness properties with lower MMA content. It was observed that the lower the concentration of TMPTA, the better the performance properties, such as tack and peel strength. It was also observed that with increasing TMPTA concentration the cohesive strength increased.

Details

Pigment & Resin Technology, vol. 40 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 4 October 2011

Ruidong Xie, Dichen Li and Shuaijun Chao

This paper seeks to describe the development of an inexpensive stereolithography (SL) system with high power ultraviolet light‐emitting diode (UV‐LED) curing light source…

Abstract

Purpose

This paper seeks to describe the development of an inexpensive stereolithography (SL) system with high power ultraviolet light‐emitting diode (UV‐LED) curing light source. The advantages of UV‐LED light source will be investigated and the results presented.

Design/methodology/approach

The working principle of the UV‐LED light‐based SL system (LED‐SL) and its characteristics were explicated; the effect of beam divergence angle on the shape of a single cured line was analyzed; and the effects of the shapes of single cured lines shone by different light sources on the fabrication accuracy were compared.

Findings

LED‐SL has significantly higher part fabrication efficiency and accuracy than UV lamplight‐based prototyping systems. Furthermore, the UV‐LED energy consumption is much lower than laser and UV lamp sources, which conforms to the requirement of Green Manufacturing.

Research limitations/implications

In increasing the scanning speed, the vibration of the focusing lens set has an obvious effect on the scanning accuracy; therefore, further research is needed.

Originality/value

This research verified the feasibility of adopting high power UV‐LED as the light source for a rapid prototyping system and enhanced the versatility of conventional UV‐SL technology.

Details

Rapid Prototyping Journal, vol. 17 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 December 2000

Chi Fo Tsang

UV curing processes of materials have to be specially designed accordingly in order to obtain the optimized property for different electronics applications. The purpose of…

Abstract

UV curing processes of materials have to be specially designed accordingly in order to obtain the optimized property for different electronics applications. The purpose of this study is to characterize and study the curing and thermal behavior of a two‐component epoxy‐based UV curable coating in electronics assembly with various thermal analysis techniques. Curing behavioral change in terms of UV light, UV exposure time, wavelength, modulus, thermal stability, organic volatile outgassing and volume was discussed. Process optimization of coating materials that were UV cured at 30°, 100° and 150°C for 1 and 10 min was further investigated. Moreover, the relationship between photocuring conditions and the resultant surface hardness was studied and correlated from the results of dynamic microhardness measurements. Thermal and hardness properties of the above processed coating materials before and after isopropyl alcohol saturation were also investigated.

Details

Microelectronics International, vol. 17 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 13 May 2020

Asfandyar Khan, Ahsan Nazir, Abdur Rehman, Maryam Naveed, Munir Ashraf, Kashif Iqbal, Abdul Basit and Hafiz Shahzad Maqsood

This review deals with the pros and cons of ultraviolet (UV) radiation on human beings and the role of textile clothing and the chemicals used for textiles to protect from…

Abstract

Purpose

This review deals with the pros and cons of ultraviolet (UV) radiation on human beings and the role of textile clothing and the chemicals used for textiles to protect from their harmful effects.

Design/methodology/approach

UV radiation (UVR) which has further divided into UVA, UVB, and UVC. Almost 100% of UVC and major portion of UVB are bounced back to stratosphere by ozone layer while UVA enters the earth atmosphere. Excessive exposure of solar or artificial UVR exhibit potential risks to human health. UVR is a major carcinogen and excessive exposure of solar radiation in sunlight can cause cancer in the lip, skin squamous cell, basal cell and cutaneous melanoma, particularly in people with the fair skin.

Findings

This article aims to provide a comprehensive overview of the harmful effects of UVR on human skin, factors affecting UV irradiance and factors affecting UV protection offered by textile clothing.

Originality/value

Effect of fiber properties, yarn properties, fabric construction, fabric treatments and laundering has been reviewed along with the identification of gaps in the reported research. A comparison of inorganic and organic UV absorbers has also been given along with different testing and evaluation methods for UV protective clothing.

Details

International Journal of Clothing Science and Technology, vol. 32 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 31 August 2010

Cliff Bowman and Véronique Ambrosini

The purpose of this paper is to address value and the value‐creation process. It argues that the firm operating in line with investor interests, acts as both a customer…

5662

Abstract

Purpose

The purpose of this paper is to address value and the value‐creation process. It argues that the firm operating in line with investor interests, acts as both a customer and a supplier of value and considers the internal activities that reflect these motivations.

Design/methodology/approach

A series of propositions are developed regarding the creation, capture and destruction of value.

Findings

It is argued that two types of value‐creating activities can be identified. In addition there are activities directed at the maintenance of the firm, and the maintenance of its capital stock, and there are activities that destroy value. Value capture is determined by bargaining relationships between stakeholders and their representatives. The paper concludes with some comments regarding value appropriation.

Originality/value

The paper addresses the critical issue of “value” in the resource‐based view (RBV) and specifically begins to develop the RBV away from its neo‐classical roots.

Details

European Business Review, vol. 22 no. 5
Type: Research Article
ISSN: 0955-534X

Keywords

Article
Publication date: 17 August 2018

Sadegh Mohajer, Rosna Mat Taha, Minoo Mohajer and Nordiyanah Anuar

This study aims to determine the appropriate irradiation dose for induction of somaclonal variation in mass of unorganized parenchyma cells derived from sainfoin …

Abstract

Purpose

This study aims to determine the appropriate irradiation dose for induction of somaclonal variation in mass of unorganized parenchyma cells derived from sainfoin (Onobrychis viciifolia) tissues.

Design/methodology/approach

To investigate the feasibility of UV-B irradiation (312 nm), seeds and callus of sainfoin were exposed to five different intensities (20-100 per cent) for evaluating the effectiveness of phytochemical constituents and cellular behaviour.

Findings

Although percentage of seed viability reduced in 20 per cent intensity of UV-B irradiation compared with control seeds, the germination speed significantly enhanced from 3.58 to 5.42. The spectrophotometer analysis confirmed that concentrations of chlorophyll (a and b) decreased after UV-B exposure as compared with control callus. Also, carotenoid content showed significant differences among treated calli. Flavonoid and phenolic contents were observed to gradually increase when the non-irradiated callus subjected to 40 and 60 per cent intensities of UV-B irradiation, respectively. Observation on cellular behaviour such as determination of nuclear and cell areas, mitotic index and chromosomal aberrations were also detected to change in different intensities of UV-B irradiation. Fragmented and aneuploidy aberrations were only observed in exposed cells with more than 40 per cent intensity of UV-B irradiation.

Originality/value

In reality, radiocytological evaluation was proven to be essential in deducing the effectiveness of UV-B irradiation to induce somaclonal variation in callus tissue of sainfoin.

Details

Pigment & Resin Technology, vol. 47 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 29 July 2020

Đorđe Vujčić, Nemanja Kašiković, Mladen Stančić, Igor Majnarić and Dragoljub Novaković

This paper aims to highlight the importance of braille for visually impaired people and the possibility of printing it by using the ultra-violet (UV) inkjet printing technique.

Abstract

Purpose

This paper aims to highlight the importance of braille for visually impaired people and the possibility of printing it by using the ultra-violet (UV) inkjet printing technique.

Design/methodology/approach

The vision impairment, definitions and statistics, as well as braille letter and standards, are first reviewed. Then, the methods of printing braille have been discussed, with a focus on UV ink-jet printing. Finally, this study indicates a significant role of UV ink-jet printed Braille, its possibilities and its advantages.

Findings

Research studies in the field of UV ink-jet printed braille are showing that it is possible to print good legible braille of the adequate height of dots. This paper highlights some advantages of printing braille with UV ink-jet, like the possibility of achieving greater dot height than embossing and no need for printing form. Printing of additional elements on top of braille dot has also been tested, and possible use for differentiation of the written notation is shown. This paper also indicates the importance of technological and operating conditions in UV inkjet braille printing. It predicts a significant role of UV inkjet in braille printing.

Originality/value

This paper provides a detailed review of UV ink-jet printed braille: possibilities, advantages and application.

Details

Pigment & Resin Technology, vol. 50 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

1 – 10 of over 4000