Indians have been considered as forerunners in the art of natural dyeing. Although indigenous knowledge system has been practiced over the years in the past, the use of natural dyes has diminished over generations due...Indians have been considered as forerunners in the art of natural dyeing. Although indigenous knowledge system has been practiced over the years in the past, the use of natural dyes has diminished over generations due to lack of documentation and precise knowledge of the extracting and dyeing techniques. As a result, natural dyes are not commercially successful. Presently, all environmentally unfriendly synthetic compounds are used for dyeing textile materials. They are non-biodegradable, carcinogenic and generate water pollution as well as waste disposal problems. Natural dyes provide a reasonable solution to these problems. Thus, it is imperative to develop technology for extraction of natural dyes and for their application on textile materials. In this study, attempt has been made to extract natural dyes from a variety of plants sources (such as rhizomes of turmeric, Curcuma longa;fruits of harda, Terminalia chebula;petals of safflower, Carthamus tinctorius;roots of barberry, Berberis lycium etc.) using specific techniques. These dyes were tested for their dyeing potential on different textile materials (cotton, silk and wool). Dyeing was done using three different dyeing techniques (pre-, simultaneous- and post-mordanting) wherein different mordants such as alum, copper sulphate and ferrous sulphate etc., were used to fix dye on to the textile material. A rainbow of natural dyes was obtained with varied shades of each colour. Shade cards were prepared for each dye and the colour obtained varied depending on the type of the mordant applied and the mordanting technique used.展开更多
In this paper, a biquad filter configuration based on two voltage differencing transconductance amplifiers (VDTAs) as newly active elements and only two capacitors as passive elements is proposed which can realize vol...In this paper, a biquad filter configuration based on two voltage differencing transconductance amplifiers (VDTAs) as newly active elements and only two capacitors as passive elements is proposed which can realize voltage-mode low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) filtering responses using three voltage inputs. Simultaneously, the same configuration can also be used to obtain LP, BP and HP filtering responses in transadmittance-mode. The proposed biquad is capable of providing electronic control of quality factor independent of pole frequency through single transconductance parameter (biasing current). It also offers the advantage of low active and passive sensitivity. To support the theoretical analysis, the PSPICE simulation of the proposed circuit is done using 0.18 μm CMOS technology from TSMC.展开更多
文摘Indians have been considered as forerunners in the art of natural dyeing. Although indigenous knowledge system has been practiced over the years in the past, the use of natural dyes has diminished over generations due to lack of documentation and precise knowledge of the extracting and dyeing techniques. As a result, natural dyes are not commercially successful. Presently, all environmentally unfriendly synthetic compounds are used for dyeing textile materials. They are non-biodegradable, carcinogenic and generate water pollution as well as waste disposal problems. Natural dyes provide a reasonable solution to these problems. Thus, it is imperative to develop technology for extraction of natural dyes and for their application on textile materials. In this study, attempt has been made to extract natural dyes from a variety of plants sources (such as rhizomes of turmeric, Curcuma longa;fruits of harda, Terminalia chebula;petals of safflower, Carthamus tinctorius;roots of barberry, Berberis lycium etc.) using specific techniques. These dyes were tested for their dyeing potential on different textile materials (cotton, silk and wool). Dyeing was done using three different dyeing techniques (pre-, simultaneous- and post-mordanting) wherein different mordants such as alum, copper sulphate and ferrous sulphate etc., were used to fix dye on to the textile material. A rainbow of natural dyes was obtained with varied shades of each colour. Shade cards were prepared for each dye and the colour obtained varied depending on the type of the mordant applied and the mordanting technique used.
文摘In this paper, a biquad filter configuration based on two voltage differencing transconductance amplifiers (VDTAs) as newly active elements and only two capacitors as passive elements is proposed which can realize voltage-mode low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) filtering responses using three voltage inputs. Simultaneously, the same configuration can also be used to obtain LP, BP and HP filtering responses in transadmittance-mode. The proposed biquad is capable of providing electronic control of quality factor independent of pole frequency through single transconductance parameter (biasing current). It also offers the advantage of low active and passive sensitivity. To support the theoretical analysis, the PSPICE simulation of the proposed circuit is done using 0.18 μm CMOS technology from TSMC.
