Judul: Rekayasa Proses Ekstraksi dan Pembuatan Pewarna Bubuk Alami dari Mahoni (Swietenia mahagoni) dan Aplikasinya untuk Pewarnaan Tekstil
Abstrak: The use of natural dyes in textile dyeing is the best option to avoid the negative impact of the carcinogenic potential contamination from synthetic dyes. Swietenia mahagoni is one of dye plant that have chemical coumpound as natural dye, such as flavonoid and tannin. Unfortunately, natural dye in Indonesia has not been widely available in the form of ready-made, such as powder form so can not be stored for a long time, the color is less stable and the process takes a long time so it is less practical in its use. The aim of this study was to extract natural dyes from wood and bark of mahagony based on optimum conditions of extraction process, determine the effect of binder treatment to the characteristics of mahagony extract colouring powder using spray dryer, and application of the natural dye in textile dyeing. The scope of this study includes the characteristics of wood and bark of mahagony, determination of appropriate type of solution (water, ethanol, metanol, ethyl acetate), determination of concentration of solution to dissolve the dye contained in the mahagony, determination of effect of binder treatment (without binder, dextrin 2% w/v, arabic gum 2% w/v) to characteristics of mahagony extracted powder, and application of natural dye powder to cotton and silk fabric with different fixative agents (without a fixative agent, alum, calcium oxide and ferrosulfate) to determine their effects on the colour of fabrics and the colour fastness to washing and sun drying treatment. The results showed that bark of mahagony and metanol solvent with concentration of 50% gave the best result on total yield and tannin content. Binder treatment had significant effect on the yield, moisture content, bulk dencity, water solubility, alcohol solubility, and colour stability. The mahagony extracted powders had the yield ranges between 3.38 – 10.36%, moisture content ranges between 6.57-7.23%, bulk density ranges between 0.051– 0.118 g/ml, solubility on water ranges between 77.56 – 81.22%, solubility on alcohol ranges between 57.26 – 92.01%, oHue ranges between 50.30 – 52.83 (red) and the best stability was found on the treatment with arabic gum binder. The fixative agents had significant effects on colour of cotton and silk fabric. Calcium oxide gave the highest colour fastness in silk fabric, while alum gave the highest result on colour fastness in cotton fabric toward washing treatment.
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Judul: The Potential of Six Plant Species Selected as Textile Natural Dyes
Abstrak: Penggunaan pewarna alami untuk tekstil memiliki keunggulan, antara lain ramah lingkungan. Penelitian ini bertujuan menganalisis potensi pemanfaatan enam jenis tumbuhan sebagai pewarna alami tekstil. Penelitian menggunakan bahan daun dari pucuk merah (Syzygium oleana), kayu manis (Cinnamomum burnamii), alpukat (Persea americana), jakaranda (Jacaranda mimosifolia), kayu putih (Eucalyptus sp.) dan lanang (Oroxylum indicum); tiga jenis mordan yaitu tawas, tunjung, kapur sirih; dan tiga jenis kain yaitu katun combed, katun primisima, dan sutera. Tahapan penelitian meliputi ekstraksi zat warna dari tumbuhan dan pencelupan kain yang sebelumnya telah diberi perlakuan mordan. Potensi sebagai pewarna dianalisis berdasarkan warna yang dihasilkan dan stabilitas warna. Identifikasi warna dilakukan menggunakan RGB (Red Green Blue) Color Chart Reader. Stabilitas warna diukur dengan uji tahan luntur warna terhadap proses pencucian mengacu SNI ISO 105-C06-2010. Penerapan ekstrak pewarna pada jenis kain berbeda yang diberi perlakuan mordan berbeda-beda menghasilkan variasi warna. Selain itu, pemberian mordan juga berpengaruh baik terhadap ketahanan luntur warna akibat pencucian. Semua ekstrak menghasilkan warna dan ketahanan luntur terbaik pada kain sutera yang diberi perlakuan mordan tunjung. Semua jenis tumbuhan dalam penelitian ini berpotensi sebagai pewarna tekstil, namun untuk mendapatkan hasil terbaik dalam penggunaannya perlu mempertimbangkan jenis kain dan mordan.
Keyword: ketahanan luntur, mordan, pewarna alami, potensi pemanfaatan tumbuhan, serat kain

Judul: Pengaruh vaksinasi terhadap dinamika populasi pada model SIR (Susceptible-Infected-Recovered)
Abstrak: SIR model can be used to model the spread of diseases in a closed population based on certain assumptions. In this research, the SIR model is formulated by including the factor of vaccination. As the result, the model has been shown to have two equilibrium points, i.e. disease free and endemic equilibrium. A simulation study is carried out to illustrate the model. The results show that some equilibrium points are asymptotically stable. Moreover, a minimum level of vaccination has been defined. For the vaccination level less than the minimum level, increase in the vaccination level results in decrease of the proportion of infected individuals in the corresponding equilibrium point. On the other hand, for the vaccination level greater than the minimum level, increase in the vaccination level results in decrease the proportion of susceptible individuals in the corresponding equilibrium point. Furthermore, when vaccination level is greater than the minimum level, it is found that the time needed for the disease to extinct is shorter.
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