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Science and Technology Indonesia
Published by Universitas Sriwijaya
ISSN : 25804405     EISSN : 25804391     DOI : -
Core Subject : Science, Social, Engineering,
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Environmental Science Materials Science & Nanotechnology Physics
An international Peer-review journal in the field of science and technology published by The Indonesian Science and Technology Society. Science and Technology Indonesia is a member of Crossref with DOI prefix number: 10.26554/sti. Science and Technology Indonesia publishes quarterly (January, April, July, October). Science and Technology Indonesia is an international scholarly journal on the field of science and technology aimed to publish a high-quality scientific paper including original research papers, reviews, short communication, and technical notes. This journal welcomes the submission of articles that covers a typical subject of natural science and technology such as: > Chemistry > Biology > Physics > Marine Science > Pharmacy > Chemical Engineering > Environmental Science and Engineering > Computational Engineering > Biotechnology Journal Commencement: October 2016
Arjuna Subject : -
Articles 16 Documents
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Search results for , issue "Vol. 6 No. 4 (2021): October" : 16 Documents clear
Time-Domain Optical Coherence Tomography System for Determining The Extinction Coefficient and Group Refractive Index of Gelatin-based Skin Phantoms Maria Cecilia Galvez; Edgar Vallar; Tatsuo Shiina; Ernest Macalalad; Paulito Mandia
Science and Technology Indonesia Vol. 6 No. 4 (2021): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2021.6.4.319-327

Abstract

Optical Coherence Tomography (OCT) is a non-invasive, non-destructive optical imaging technique that uses a low coherence interferometer to obtain real-time cross-sectional images of samples. OCT is notably used in biomedical applications including ophthalmology and dermatology. Aside from generating cross-sectional images, axial scans can also provide additional information about its optical properties such as extinction coefficient and refractive index. This study determines the extinction coefficients and group refractive indices of gelatin-based skin phantoms using a portable time-domain (TD) – OCT system. The gelatin-based skin phantoms were fabricated with varying concentrations of titanium dioxide (TiO2), while keeping the amount of both gelatin and water constant. By changing the proportion of the gelatin powder and TiO2, skin phantoms can then be fabricated to mimic various skin conditions, both pathologic and non-pathologic. Results of the study found a positive correlation of extinction coefficient and refractive index with TiO2 concentration. Thus, increasing TiO2 concentration also increases both extinction coefficient and group refractive index. The median extinction coefficient values of the phantoms ranged from 4.29 mm−1 to 8.48 mm−1. Literature showed that the epidermis can have extinction coefficients of 1.64-7.3 mm−1. For refractive indices of the fabricated phantoms, values ranged from 1.32 to 1.48, while studies on human participants showed that human skin has refractive index values of 1.34-1.56. Based on these properties, it is feasible to fabricate phantoms simulating the optical properties of human skin.
Prediction of Plastic-Type for Sorting System using Fisher Discriminant Analysis Irsyadi Yani; Yulia Resti; Firmansyah Burlian; Ansyori Yani
Science and Technology Indonesia Vol. 6 No. 4 (2021): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2021.6.4.313-318

Abstract

Recycling is a more environmentally friendly method of managing and reducing plastic waste that can significantly reduce land degradation, pollution, and greenhouse gas emissions. According to its composition, an essential first step in the recycling process is sorting out plastic waste. However, inadequate sorting of plastic types can result in cross-contamination and increasing industrial operating costs. A low-cost automated plastic sorting system can be developed by using digital image data in the red, green, and blue (RGB) color space as the dataset and predicting the type using learning datasets. The purpose of this paper is to demonstrate how to use Fisher Discriminant Analysis (FDA) to predict the plastic type from a digital image of the RGB model and then evaluate the performance using cross-validation. This work has four main steps: collecting plastic digital image data, forming statistical tests, predicting plastic types, and evaluating prediction performance. FDA is quite effective for predicting the type of plastic. Performance measures the accuracy of 87.11 %, the recall-micro of 91.67 %, the recall-micro of 80.97 %, the specificity-micro of 90.33 %, and the specificity-macro of 90.38 %, respectively. The micro is determined by the number of decisions made for each object. In comparison, the macro is calculated based on the average decision made by each class.
Polyisoprenoid Compounds from Tropical Fruit Trees in Universitas Sumatera Utara Campus Muttia Chandraputri Rizkiany; Rizka Amelia; Yuntha Bimantara; Hiroshi Sagami; Mohammad Basyuni
Science and Technology Indonesia Vol. 6 No. 4 (2021): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2021.6.4.267-272

Abstract

Tropical trees are a source of secondary metabolite compounds that have various biological activities that can help human life both for industrial and pharmaceutical needs. One of the secondary metabolites is polyisoprenoid. This study aims to identify and analyze polyisoprenoid compounds quantitatively from tropical fruit trees at the Universitas Sumatera Utara. Nine samples of tropical fruit were obtained, namely: Psidium guajava, Tamarindus indica, Manilkara kauki, Morinda citrifolia, Mangifera indica, Artocarpus communis, Artocarpus heterophyllus, Gmelina arborea, and Syzygium aqueum. Each sample was extracted and isolated the polyisoprenoid alcohol, then analyzed using two-dimensional thin-layer chromatography. The polyisoprenoid in fruit samples found at the Universitas Sumatera Utara was a type II and III polyisoprenoid compound. The total lipid values ranged from 48.7 mg/g dw to 262.9 mg/g dw, polyisoprenoids ranged from 1.2 mg/g dw to 9.5 mg/g dw, and polyprenols ranged from 0.5 mg/g dw to 5.7 mg/g dw. Carbon chain length and dolichol polyprenol lengths of each fruit were collected (Psidium guajava L.) (C70 C80), (Tamarindus indica L.) (C80 C95), (Manilkara kauki L.) (C80 C95 and C70 C90), (Morinda citrifolia L.) (C75 C100), (Mangifera indica L.) (C80 C90 and C75 C90), (Artocarpus communis) (C75 C95), (Artocarpus heterophyllus) (C70 C75 and C70 C100), (Gmelina arborea Roxb.) (C90 C95), and (Syzygiumaqueum) (C65 C90 and C75 C90).
Biogenic Silica Extracted from Salacca Leaves Ash for The Adsorption of Salycilic Acid Is Fatimah; Faiha Ulfiyani Zaenuri; Lolita Narulita Doewandono; Amri Yahya; Putwi Widya Citradewi; Suresh Sagadevan; Won-Chun Oh
Science and Technology Indonesia Vol. 6 No. 4 (2021): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2021.6.4.296-302

Abstract

Extraction of biogenic silica from Salacca leaves ash and it’s utilization as adsorbent for salycilic acid has been successfully conducted. The caustic extraction by Refluxing the ash in NaOH followed by slow titration using acid produced the silica gel, and in order to evaluate the physicochemical character for adsorption purpose, the sintering of the dried gel was varied at 300, 400 and 500oC. Instrumental analysis of x-ray diffraction, scanning electron microscopy, gas sorption analysis, and Fourier transform infrared spectroscopy were employed. The kinetics of the salycilic acid adsorption was investigated in a batch adsorption system and the quantitative analysis was based on UV–Vis spectrometry. The results showed that the produced silica exhibited adsorption capability for salycilic acid in an aqueous solution. At varied sintering temperature, the highest adsorption capacity and affinity was achieved by temperature of 500oC, and the adsorption kinetics obeyed the Langmuir isotherm. The varied pH for adsorption suggested neutral pH is the most feasible compared to the acidic and basic conditions.
Determining The Number of Connected Vertex Labeled Graphs of Order Seven without Loops by Observing The Patterns of Formula for Lower Order Graphs with Similar Property Muslim Ansori; Wamiliana; Fadila Cahya Puri
Science and Technology Indonesia Vol. 6 No. 4 (2021): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2021.6.4.328-336

Abstract

Given n vertices and m edges, m ≥ 1, and for every vertex is given a label, there are lots of graphs that can be obtained. The graphs obtained may be simple or not simple, connected or disconnected. A graph G(V,E) is called simple if G(V,E) not containing loops nor paralel edges. An edge which has the same end vertex is called a loop, and paralel edges are two or more edges which connect the same set of vertices. Let N(G7,m,t) as the number of connected vertex labeled graphs of order seven with m vertices and t (t is the number edges that connect different pair of vertices). The result shows that N(G7,m,t) = ct C (m−1) t−1, with c6=6727, c7=30160 , c8=30765, c9=21000, c10=28364, c11=26880, c12=26460, c13=20790, c14=10290, c15= 8022, c16=2940, c17=4417, c18=2835, c19=210, c20= 21, c21=1.
Analysis of Information Service Pricing Scheme Model Based on Customer Self-Selection Indrawati; Fitri Maya Puspita; Resmadona; Evi Yuliza; Oki Dwipurwani; Sisca Octarina
Science and Technology Indonesia Vol. 6 No. 4 (2021): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2021.6.4.337-343

Abstract

This study attempts to analyze pricing schemes with monitoring cost and marginal cost for perfect substitute and quasi-linear utility functions for achieving Internet service Provider (ISP) in gaining benefit. Two types of customers analyzed, namely customers who are heterogeneous (both high-end and low-end) as well as heterogeneous customers (high-demand and low-demand) based on Flat-fee, usage-based, and two-part tariff are the three types of pricing methods employed. The results show that usage-based pricing schemes gain maximum profit optimal for heterogeneous customers (high-end and low-end), while for heterogeneous customers (high-demand and low-demand) type of pricing scheme two-part tariff obtains maximum profit optimal. The results of this study are more directed to the lemma of the perfect substitute utility function which compares the lemma of heterogeneous customers. This model was solved using LINGO 13.0 software and ISP to get maximum profit.

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