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1 – 10 of over 4000Photoresist 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…
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.
Shuo Su, Xiong-Tao Zhu and Hong-Qiang Fan
This paper aims to study the effect of ultraviolet (UV) light on the corrosion behavior of BC550 weathering steel in simulated marine atmospheric environment.
Abstract
Purpose
This paper aims to study the effect of ultraviolet (UV) light on the corrosion behavior of BC550 weathering steel in simulated marine atmospheric environment.
Design/methodology/approach
The effect of UV light on the corrosion behavior of BC550 weathering steel in simulated marine atmospheric environments were investigated by the corrosion weight gain experiment, in situ electrochemical noise, scanning electron microscope and X-ray diffraction.
Findings
UV light accelerated the corrosion process of BC550 weathering steel in the simulated marine atmospheric environment during the first 168 h. The maximum influence factor of UV light was 0.32, and it was only 0.08 after 168 h of corrosion process.
Originality/value
As the extension of corrosion time, the thickness and density of the corrosion product layer increased, which weakened the acceleration effect of UV light.
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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 cohesive…
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.
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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. The…
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.
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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…
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.
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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 their…
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.
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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 edodes)…
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.
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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 and a…
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.
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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 (Onobrychis…
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.
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.
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