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Article
Publication date: 4 November 2022

Hyunah Kim

This study examined the wear comfort and thermal insulation properties of Al2O3/graphite particle-imbedded sheath/core and dispersed fabrics via a thermal manikin experiment.

Abstract

Purpose

This study examined the wear comfort and thermal insulation properties of Al2O3/graphite particle-imbedded sheath/core and dispersed fabrics via a thermal manikin experiment.

Design/methodology/approach

Al2O3/graphite sheath/core and dispersed polyethylene terephthalate (PET) yarn (POY 120d/24f) were spun using a pilot melt bi-component conjugated spinning machine, which was texturized as 75d/24f on the belt-type texturing machine. The woven fabric specimens were made using nylon 70d/34f in the warp with three types of weft yarn: Al2O3/graphite sheath/core, dispersed and regular PET yarns. Thermal insulation properties were measured and compared in terms of the heat retention rate (I) by KES-F7 apparatus and the maximum surface temperature by light heat emission equipment, as verified by the emissivity of various fabric specimens by far-infrared ray experiment. In addition, this study examined the thermal insulation (Clo value) characteristics of the clothes made of Al2O3/graphite sheath/core and dispersed fabrics using a thermal manikin apparatus, which were compared with the properties of regular PET clothing.

Findings

The thermal insulation of the dispersed fabric was superior to that of the sheath/core fabric, which was tentatively attributed to the higher emissivity of the dispersed yarn with Al2O3/graphite particles distributed over the whole yarn cross-section than that from the core of the sheath/core yarn. This result for the clothing measured using a thermal manikin was consistent with the higher heat retention rate (I) and the maximum surface temperature of the dispersed fabric than that of the sheath/core fabric. In addition, the thermal insulation of the dispersed and sheath/core fabrics was superior to that of the regular PET fabric, which revealed that the Al2O3/graphite particles imbedded in the dispersed and sheath/core yarns exerted a greater effect on the heat storage and release characteristics compared to that of the TiO2 particles in regular PET yarn. The Clo values of the dispersed and sheath/core fabrics under the light-on condition were much higher than those under the light-off condition, and furthermore, the difference of the Clo value between the sheath/core and regular PET fabrics under light-on condition was approximately 1.7 times greater than that under the light-off condition. These results revealed that the far-infrared rays emitted from the Al2O3/graphite particles imbedded in the sheath/core and dispersed yarns enhance the heat storage and release characteristics from the fabric under the light-on condition, i.e. under the sunlight.

Originality/value

The previously examined thermal wear comfort properties of the various inorganic particle-imbedded fabrics were measured with the fabric state, not clothing, which could not provide objective data related to the actual wearing performance of clothing.

Details

International Journal of Clothing Science and Technology, vol. 35 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 1 January 1992

P.V. Natarajan, D.G. Vaiude and B.M. Rao

This paper concerns an all‐solid‐state, high‐contrast electroluminescent (EL) flat panel display which is becoming the potential for multifunctional avionic displays. In this…

Abstract

This paper concerns an all‐solid‐state, high‐contrast electroluminescent (EL) flat panel display which is becoming the potential for multifunctional avionic displays. In this ACTFEL (a.c. thin film electroluminescent flat panel) device, an active layer, doped with manganese (ZnS:Mn) is sandwiched between the two dielectric layers followed by conductive layers. All the layers are transparent except the back conductive layer. In the basic mode of operation, an alternating voltage is applied across any two crossing electrodes. When this voltage exceeds the ‘threshold voltage’, light is emitted from the active layer. EL mechanism (the generation of electrons, acceleration of these electrons to optical energies, and collision excitation of the Mn ions yielding light emission) occurs within the film or at the surface of the ZnS:Mn layer. A bright yellow light, in the visible region and with a relatively broad spectrum, is emitted. The TFEL display's thinness, compactness, low weight, moderately low power requirements and durability are its prime advantages. The characteristics of various thin films utilised in TFEL have been studied, and the data in this paper show the optimum requirements for luminance, efficiency and reliability of the light emission in ACTFEL.

Details

Microelectronics International, vol. 9 no. 1
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 2 November 2015

Zi-qian Bai, Jeanne Tan, Clare Frances Johnston and Xiao-Ming Tao

The purpose of this paper is to investigate how electronic components can be utilized and integrated into polymeric optical fibre (POF) textiles to refine the design aesthetic…

Abstract

Purpose

The purpose of this paper is to investigate how electronic components can be utilized and integrated into polymeric optical fibre (POF) textiles to refine the design aesthetic, tactile quality and initiate the interaction of textiles with the users; and to study the design process of interactive products by using a novel design process model.

Design/methodology/approach

Fashion and textile design methods, textile technology are used in combination with modern technologies such as laser engraving, sensing, short-distance communication technology, throughout the entire process of development of interactive photonics creations.

Findings

The results of evaluation indicate that the engineered prototypes can enhance the interactive function of interior furnishing. The usability of interactive POF cushions is optimized by innovative design methods considering both design and technology.

Originality/value

This research explores to combine knowledge from different disciplines, including textile, electronics, sensor and laser to create interactive soft furnishings. The inter-disciplinary research provides a new perspective on how POF fabric can be utilized as a new media to change the way people interact with their living surroundings. The interior soft furnishings are no longer unresponsive to people, but can react to them, adapt to their behaviors, change color according to their preferences and therefore merge into our daily life. The developed prototypes reshape interior soft furnishing, and therefore have both theoretical and practical significance.

Details

International Journal of Clothing Science and Technology, vol. 27 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 6 November 2009

C.B. Li, G.X. Yang, Z.H. Huang, Y. Xin, C. Wang and J.H. Yuan

The purpose of this paper is to focus on the development of highly efficient emission materials for light‐emitting diodes (LEDs).

Abstract

Purpose

The purpose of this paper is to focus on the development of highly efficient emission materials for light‐emitting diodes (LEDs).

Design/methodology/approach

The equilibrium geometries of silole‐based derivatives are optimised by means of DFT/B3LYP method with the 6‐31G(d) basis set in this paper. The geometries of single‐excitation are optimised using the ab initio configuration interaction with single excitations/6‐31G(d), the first singlet excited states and optical properties are calculated by using time‐dependent density‐functional theory based on the 6‐31G(d) basis set.

Findings

The highest occupied molecular orbital and lowest unoccupied molecular orbital suffer larger effects from the variation of the substituent groups of methyls and phenyls. The absorption wavelengths of all the cases are similar, but the emission wavelengths are significantly different.

Research limitations/implications

Solid‐state stacking effect is not included in this paper.

Originality/value

In view of the application of silole‐based derivatives systems, the control of photophysical properties and electronic structures by structural modification is relevant to further molecular design.

Details

Pigment & Resin Technology, vol. 38 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 March 2002

Alex Alaluf and David Birnbaum

Examines the use of laser‐induced fluorescence for the inspection of printed circuit boards. Discusses how it works, how it compares with other inspection options and what…

Abstract

Examines the use of laser‐induced fluorescence for the inspection of printed circuit boards. Discusses how it works, how it compares with other inspection options and what advantages it offers, particularly for the inspection of low‐contrast materials. Concludes that laser‐based automated optical inspection (AOI) has major potential advantages compared with white‐light AOI equipment.

Details

Circuit World, vol. 28 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 16 January 2009

Jae‐Won Choi, Ryan B. Wicker, Seok‐Hyun Cho, Chang‐Sik Ha and Seok‐Hee Lee

The paper's aim is to explore a method using light absorption for improving manufacturing of complex, three‐dimensional (3D) micro‐parts with a previously developed dynamic mask…

3234

Abstract

Purpose

The paper's aim is to explore a method using light absorption for improving manufacturing of complex, three‐dimensional (3D) micro‐parts with a previously developed dynamic mask projection microstereolithography (MSL) system. A common issue with stereolithography systems and especially important in MSL is uncontrolled penetration of the ultraviolet light source into the photocrosslinkable resin when fabricating down‐facing surfaces. To accurately fabricate complex 3D parts with down‐facing surfaces, a chemical light absorber, Tinuvin 327™ was mixed in different concentrations into an acrylate‐based photocurable resin, and the solutions were tested for cure depths and successful micro‐part fabrication.

Design/methodology/approach

Tinuvin 327 was selected as the light absorber based on its high absorption characteristics (∼0.4) at 365 nm (the filtered light wavelength used in the MSL system). Four concentrations of Tinuvin 327 in resin were used (0.00, 0.05, 0.10, and 0.15 percent (w/w)), and cure depth experiments were performed. To investigate the effects of different concentrations of Tinuvin 327 on complex 3D microstructure fabrication, several microstructures with overhanging features such as a fan and spring were fabricated.

Findings

Results showed that higher concentrations of Tinuvin 327 reduced penetration depths and thus cure depths. For the resin with 0.15 percent (w/w) of the Tinuvin 327, a cure depth of ∼30 μm was achieved as compared to ∼200 μm without the light absorber. The four resin solutions were used to fabricate complex 3D microstructures, and different concentrations of Tinuvin 327 at a given irradiance and exposure energy were required for successful fabrication depending on the geometry of the micro‐part (concentrations of 0.05 and 0.1 percent (w/w) provided the most accurate builds for the fan and spring, respectively).

Research limitations/implications

Although two different concentrations of light absorber in solution were required to demonstrate successful fabrication for two different micro‐part geometries (a fan and spring), the experiments were performed using a single irradiance and exposure energy. A single solution with the light absorber could have possibly been used to fabricate these micro‐parts by varying irradiance and/or exposure energy, although the effects of varying these parameters on geometric accuracy, mechanical strength, overall manufacturing time, and other variables were not explored.

Originality/value

This work systematically investigated 3D microstructure fabrication using different concentrations of a light absorber in solution, and demonstrated that different light absorption characteristics were required for different down‐facing micro‐features.

Details

Rapid Prototyping Journal, vol. 15 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 June 2005

Uri Fidelman

This is a continuation of Parts I and II of the paper. In this part it is suggested that microscopic particles behave similarly to macroscopic objects: Features of two entangled…

234

Abstract

Purpose

This is a continuation of Parts I and II of the paper. In this part it is suggested that microscopic particles behave similarly to macroscopic objects: Features of two entangled particles, having the same “dimension” (kind of feature), may interchange and migrate from one particle to the other while their wave function collapses. In the particular case of electrically charged particles, like an electron and a proton, the migrating features that are interchanged between the particles, may be the electrical charges (that have the same “dimension”). This implies that each atom of matter has some very small probability to be an atom of antimatter, and it may be annihilated if it collides with an atom of matter. The purpose of this study is to suggest how this hypothesis may be tested empirically.

Design/methodology/approach

The cooler are the molecules of gases, the slower they are. Therefore, according to Heisenberg's principle of uncertainty, the probability that gaseous molecules will collide increases when the gas is cooled.

Findings

We may expect that when gases are cooled there is a higher than usual probability that gaseous molecules of matter and antimater will collide and will annihilate each other, emitting photons of gamma rays. Such findings has been reported by Molchadzki, but not explained. The same is true regarding other situations in which the probability of collisions of gaseous molecules is higher than the usual, like the colliding of gaseous molecule at the center of an imploding bubble of gas.

Originality/value

If a procedure that increases the number of collisions between gaseous molecules considerably will be developed, it may be that this procedure will be applicable for obtaining clean energy by annihilations of matter and antimatter.

Details

Kybernetes, vol. 34 no. 5
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 12 July 2013

D. Křemenáková, J. Militký, B. Meryová and V. Lédl

The main role of polymer optical fibers is to transmit light or optical signal to a specified spot. In the case of side emitting plastic optical fibers the light leaks out from…

Abstract

The main role of polymer optical fibers is to transmit light or optical signal to a specified spot. In the case of side emitting plastic optical fibers the light leaks out from their surface. This sidelight can be used for creation of optically active textile structures providing opportunities to highlight people and objects without the need for external exposure. Due to the transmission loss, the intensity of radiation emitted in any direction decays exponentially along the fiber axis with increasing distance from the light source. The main aim of this contribution is evaluation of side emitting plastic optical fibers light intensity in dependence on the distance from light source. The special device for measurement of surface and cross section light intensity in various distances from light source was developed. The dependence of surface and cross section light intensity on the distance from light source will be expressed by the exponential type model with attenuation factor as the rate parameter. The influence of the optical fiber type and diameter on the attenuation factor of surface and cross section light intensity will be quantified.

Details

World Journal of Engineering, vol. 10 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 29 August 2018

Nwakaego Chikaodinaka Onyenokporo and Ekele Thompson Ochedi

The purpose of this paper is to develop a set of affordable retrofit packages that can be applied to existing residential buildings in hot-humid regions to improve occupants’…

Abstract

Purpose

The purpose of this paper is to develop a set of affordable retrofit packages that can be applied to existing residential buildings in hot-humid regions to improve occupants’ thermal comfort and reduce energy consumption.

Design/methodology/approach

A critical review of relevant literature to identify passive design strategies for improving thermal comfort and reducing energy consumption in hot-humid climates with focus on the building envelope was conducted in addition to a simulation study of an existing building typology in study area.

Findings

There is enormous potential to reduce energy costs and improve thermal comfort through building retrofit packages which is a recent concept in developing countries, such as Nigeria. Analysing the results of the retrofit interventions using building energy simulation helped in developing affordable retrofit packages which had optimum effect in improving indoor comfort temperature to the neutral temperature specified for hot humid Nigeria and further down to 3°C less than that of the reference building used. The use of passive design strategies to retrofit the building might help homeowners reduce their annual energy consumption by up to 46.3 per cent just by improving the indoor thermal comfort.

Originality/value

In addition to improving thermal comfort and reducing energy consumption, this research identified affordable retrofit packages and considered its cost implications especially to low-income earners who form a larger population of Lagos, Nigeria, as this was not considered by many previous researchers.

Details

International Journal of Building Pathology and Adaptation, vol. 37 no. 3
Type: Research Article
ISSN: 2398-4708

Keywords

Article
Publication date: 8 July 2021

Muhammad Esmed Alif Samsudin, Yusnizam Yusuf, Norzaini Zainal, Ahmad Shuhaimi Abu Bakar, Christian Zollner, Michael Iza and Steven P. DenBaars

The purpose of this study is to investigate the influence of AlN nucleation thickness in reducing the threading dislocations density in AlN layer grown on sapphire substrate.

Abstract

Purpose

The purpose of this study is to investigate the influence of AlN nucleation thickness in reducing the threading dislocations density in AlN layer grown on sapphire substrate.

Design/methodology/approach

In this work, the effect of the nucleation thickness at 5 nm, 10 nm and 20 nm on reducing the dislocation density in the overgrown AlN layer by metal organic chemical vapor deposition was discussed. The AlN layer without the nucleation layer was also included in this study for comparison.

Findings

By inserting the 10 nm thick nucleation layer, the density of the dislocation in the AlN layer can be as low as 9.0 × 108 cm−2. The surface of the AlN layer with that nucleation layer was smoother than its counterparts.

Originality/value

This manuscript discussed the influence of nucleation thickness and its possible mechanism in reducing dislocations density in the AlN layer on sapphire. The authors believe that the finding will be of interest to the readers of this journal, in particular those who are working on the area of AlN.

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