1,722,657 research outputs found
Antimicrobial functionalization of technical textiles for medical, aerospace and civil applications
Full text linkTextiles, today, are no more just traditional textiles. With the advancements in nano and fiber technology, they find various technical applications and are known as technical textiles. Antimicrobial functionalization is an integral requirement for some of these applications that include medical textiles, aerospace textiles and textiles used in filtration. Various organic and inorganic antimicrobial agents are being explored for antimicrobial functionalization of textiles with the objective to obtain effective, durable and broad spectrum antimicrobial properties. However, these antimicrobial agents may have their own advantages and disadvantages. Some of them may lack broad spectrum antimicrobial properties as well as complex method of their synthesis and application which may not always be environmental friendly.
Silver is well known inorganic antimicrobial agent with effective antimicrobial action against broad spectrum of microbes. Silver is being intensively studied in nano particle form for the functionalization of textiles. However, mostly the synthesis and application of silver nano particles to textiles is carried through wet routes. These may have environmental considerations due to possible use of toxic reducing and stabilizing agents. In addition their solution or colloidal based application to textiles is intense in water and energy consumption along with production of waste water and necessitating its treatment. This may not help reduce environmental burden of textile industry which is regarded as one of the most polluting industrial sector of the world. Therefore, along with providing antimicrobial protection, the process of obtaining antimicrobial textiles itself should not create adverse environmental impact.
In this context, ecofriendly processes for textile industry have always been in focus of research. The objective of this thesis was to achieve “antimicrobial functionalization of technical textiles for medical, aerospace and civil applications” via a simple and single step environment friendly technique known as radio frequency “co-sputtering”. Sputtering is a plasma based process and is mostly used in automotive, tools and electronics industry. It is not yet fully explored in textile industry. This study aimed at obtaining antimicrobial textiles via co-sputtering and exploring some of the its key strengths and weaknesses for textiles.
In the adopted co-sputtering technique, an antimicrobial silver nano clusters/silica composite coating was deposited on four different textile substrates. The deposition parameters of both silica and silver were controlled independently such that silica constituted the matrix of the composite coating and silver was deposited in the form of nano clusters embedded in the silica matrix. The four textile substrates used in this study were: cotton fabric intended for medical applications, high performance Kevlar® and Vectran® fabrics for aerospace applications and activated carbon fabric (ACF) to be used in air filtration.
The morphology and composition of the deposited coating was investigated in detail using FESEM, EDX and XPS which showed that silver nano clusters (25-50 nm) were uniformly distributed and firmly embedded in the silica matrix. Total silver concentration in the composite coating was evaluated through ICP_MS and was found to be dependent on deposition time and thus on coating thickness. Silver ion release test in water and in artificial sweat showed a progressive and gradual release of silver ions, beneficial for prolonged antimicrobial activity. The nature of the fabric substrate was also found to influence the release of silver ions. The coating showed effective antimicrobial properties against Gram positive (S. aureus, S. epidermidis), Gram negative (E. coli) bacteria and fungus (C. albicans) with varying intensity of the action depending upon the microbe as well as silver ion release profiles. Water contact angle and sorption tests revealed hydrophilic nature of the coating. Moisture management properties evaluated by Moisture Management Tester showed that coating imparted fast absorbing and quick drying characteristic to the fabric. The coating was highly conformal and did not altered air permeability of the substrates which is a highly desirable characteristic to preserve thermo physiological comfort of the fabric as well as maintain filtration capacity of ACF. However, the washing stability of the coating was found not to be completely satisfactory.
The work was carried with in the frame wok of an Italian regional project with several other project partners. Some results from these partners, duly acknowledged, are also discussed in this thesis and summarized in conclusion
Joint geometry and color denoising for 3D point clouds
Full text linkL'abstract è presente nell'allegato / the abstract is in the attachmen
Animalia Tanasevitch 2019
No full textGenus Parbatthorax Tanasevitch, 2019 Type species Parbatthorax unicornis Tanasevitch, 2019.Published as part of Irfan, Muhammad & Peng, Xianjin, 2019, The genus Parbatthorax Tanasevitch, 2019 (Araneae, Linyphiidae) new to China, with a new species from the Gaoligong Mountains, pp. 1-11 in European Journal of Taxonomy 555 on page 2, DOI: 10.5852/ejt.2019.555, http://zenodo.org/record/347028
Five new species of Otacilia Thorell, 1897 (Araneae: Phrurolithidae) from the Wuling Mountain Range, China
No full textYao, Na, Irfan, Muhammad, Peng, Xianjin (2019): Five new species of Otacilia Thorell, 1897 (Araneae: Phrurolithidae) from the Wuling Mountain Range, China. Zootaxa 4613 (2): 290-304, DOI: 10.11646/zootaxa.4613.2.
Point Cloud Denoising using Joint Geometry/Color Graph Wavelets
Full text linkA point cloud is a 3D geometric signal representation associated with other attributes such as color, normal, trans parency. Point clouds usually suffer from noise due to imperfect acquisition systems. Based on the notion that geometry and color are correlated, we present a novel non-iterative framework for point cloud denoising using Spectral Graph Wavelet transform (SGW) that takes advantage of this correlation and performs denoising in the graph frequency domain. The proposed approach is based on the design of a joint geometry and color graph that compacts the energy of smooth graph signals in low-frequency bands. We then apply soft-thresholding to remove the noise from the spectral graph wavelet coefficients. Experimental results show that the proposed technique significantly outperforms state-of-the-art methods
Exploiting color for graph-based 3D point cloud denoising
Full text linkA point cloud is a representation of a 3D scene as a discrete collection of geometry plus other attributes such as color, normal, transparency associated with each point. The traditional acquisition process of a 3D point cloud, e.g. using depth information acquired directly by active sensors or indirectly from multi-viewpoint images, suffers from a significant amount of noise. Hence, the problem of point cloud denoising has recently received a lot of attention. However, most existing techniques attempt to denoise only the geometry of each point, based on the geometry information of the neighboring points; there are very few works at all considering the problem of denoising the color attributes of a point cloud. In this paper, we move beyond the state of the art and we propose a novel technique employing graph-based optimization, taking advantage of the correlation between geometry and color, and using it as a powerful tool for several different tasks, i.e. color denoising, geometry denoising, and combined geometry and color denoising. The proposed method is based on the notion that the correct location of a point also depends on the color attribute and not only the geometry of the neighboring points, and the correct color also depends on the geometry of the neighbors. The proposed method constructs a suitable k-NN graph from geometry and color and applies graph-based convex optimization to obtain the denoised point cloud. Extensive simulation results on both real-world and synthetic point clouds show that the proposed denoising technique outperforms state-of-the-art methods using both subjective and objective quality metrics
Joint geometry and color point cloud denoising based on graph wavelets
Full text linkA point cloud is an effective 3D geometrical presentation of data paired with different attributes such as transparency, normal and color of each point. The imperfect acquisition process of a 3D point cloud usually generates a significant amount of noise. Hence, point cloud denoising has received a lot of attention. Most of the existing techniques perform point cloud denoising based only on the geometry information of the neighbouring points; there are very few works considering the problem of denoising of color attributes of a point cloud, and taking advantage of the correlation between geometry and color. In this article, we introduce a novel non-iterative set-up for the denoising of point cloud based on spectral graph wavelet transform (SGW) that jointly exploits geometry and color to perform denoising of geometry and color attributes in graph spectral domain. The designed framework is based on the construction of joint geometry and color graph that compacts the energy of smooth graph signals in the low-frequency bands. The noise is then removed from the spectral graph wavelet coefficients by applying data-driven adaptive soft-thresholding. Extensive simulation results show that the proposed denoising technique significantly outperforms state-of-the-art methods using both subjective and objective quality metrics
FIGURE 1. Herbiphantes acutalis n in Herbiphantes Tanasevitch, 1992 and Labullinyphia van Helsdingen, 1985 (Araneae Linyphiidae), two newly recorded spider genera from the Gaoligong Mountains in China with the description of two new species
No full textFIGURE 1. Herbiphantes acutalis n. sp., male holotype (A–C) and female paratype (D–F). A, D, Habitus, dorsal view. B, E, Habitus, lateral view. C, F Habitus, ventral view. Scale bars, 1 mm.Published as part of Irfan, Muhammad & Peng, Xianjin, 2019, Herbiphantes Tanasevitch, 1992 and Labullinyphia van Helsdingen, 1985 (Araneae Linyphiidae), two newly recorded spider genera from the Gaoligong Mountains in China with the description of two new species, pp. 547-561 in Zootaxa 4638 (4) on page 549, DOI: 10.11646/zootaxa.4638.4.5, http://zenodo.org/record/334048
FIGURE 88. Erigone atra Blackwall, 1833, palp. A dorsal view B, D retrolateral view C prolateral view E in Survey of Linyphiidae (Arachnida: Araneae) spiders from Yunnan, China
No full textFIGURE 88. Erigone atra Blackwall, 1833, palp. A dorsal view B, D retrolateral view C prolateral view E ventral view.Published as part of Irfan, Muhammad, Zhang, Zhi-Sheng & Peng, Xian-Jin, 2022, Survey of Linyphiidae (Arachnida: Araneae) spiders from Yunnan, China, pp. 1-292 in Megataxa 8 (1) on page 80, DOI: 10.11646/megataxa.8.1.1, http://zenodo.org/record/752657
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