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Isolation and Identification of Flavonoid Compounds From the Bark of Eukaliptus (Eucalyptus grandis W. Hill ex Maiden)
No full textThe isolation and identification of flavonoid compounds obtained from the
bark of eucalyptus tree (Eucalyptus grandis W. Hill ex Maiden) was carried out
using several methods, namely maceration extraction with methanol as the solvent,
partition extraction with ethyl acetate and n-hexane, yielding an ethyl acetate
extract. The concentrated ethyl acetate extract was then analyzed using Thin Layer
Chromatography (TLC) and subsequently separated by column chromatography
using a stationary phase of silica gel and n-hexane : ethyl acetate (90:10; 80:20;
70:30; 60:40; 50:50; 40:60; 30:70; 20:80; 10:90) v
/v as the mobile phase. Fraction
three were purified using preparative TLC with chloroform : ethyl acetate (40:60) v
/v
as the mobile phase. The isolated compound was a 4 mg brown amorphous solid with
an Rf value of 0.48 using chloroform:ethyl acetate (40:60) v
/v as the eluent.
Furthermore, UV-Visible spectrophotometric analysis showed two absorption bands,
the first at 315 nm and the second at 257 nm. Analysis with the Infrared
spectrophotometric (FT-IR) an O–H functional group with an stretching vibration at
a wavenumber 3408.22 cm⁻¹, C=O ketone with an stretching at a wavenumber
1689.64 cm⁻¹, and C–O–C symmetric stretching at 1029.99 cm⁻¹. The ¹H-NMR
spectrum, a characteristic proton signal for H-2 at δ 8.54 ppm, which is typical for
isoflavone compounds. Based on the spectroscopic data, the isolated compound was
identified as a flavonoid belonging to the isoflavone class.64 PagesSkripsi Sarjan
The Influence Of Influencer Marketing and Fear Of Missing Out (Fomo) on Impulse Buying Among Generation-Z Tiktok Users In Medan City (A Case Study on Rucas.Co)
No full textThis study aims to examine and analyze the influence of Influencer Marketing and Fear of Missing Out (FOMO) on Impulse Buying among Rucas.co customers in Medan City. This research is associative in nature, using primary data obtained through questionnaires distributed to Rucas.co consumers. The population of this study consists of all consumers who have ever purchased Rucas.co products, with a sample size of 110 respondents determined using Hair’s formula. The data analysis technique employed is multiple linear regression analysis. The results indicate that Influencer Marketing and Fear of Missing Out simultaneously have a significant effect on Impulse Buying among Rucas.co customers. Partially, Influencer Marketing has a positive and significant effect on Impulse Buying, and similarly, Fear of Missing Out (FOMO) has a positive and significant effect on Impulse Buying. This finding shows that promotional strategies through influencers and the psychological drive of FOMO can encourage consumers to make impulsive purchases.114 PagesSkripsi Sarjan
Compressive Strength of Scaffold Based on Nile Tilapia Fish Scale Nano-Hydroxyapatite and Commercial Gelatin Using Porogen Leaching Method with Different Weight Concentration Ratios.
No full textBone defects exceeding the critical size threshold (>2 cm) require medical interventions to prevent pathological fractures that cannot be naturally supported by the body. One potential solution is the use of nano-hydroxyapatite (nHAp)-based scaffold synthesized from tilapia fish scales (Oreochromis niloticus), which exhibit a Ca/P ratio of 1.67. This study aimed to analyze the compressive strength of scaffolds fabricated from combinations of nHAp and commercial gelatin at weight percentage ratios of 20:10, 30:15, and 40:20. The samples consisted of scaffolds with a diameter of 6.5 mm and a thickness of 10.8 mm, prepared from nano-hydroxyapatite synthesized from tilapia fish scales using calcination and alkaline heat treatment methods. A total of 30 samples were produced and divided into three groups (n = 10) based on the HA-to-gelatin weight ratios: 20:10 (Group I), 30:15 (Group II), and 40:20 (Group III). The scaffolds were fabricated using the porogen leaching method followed by calcination at 800°C. Compressive strength testing was conducted using a Universal Testing Machine. The results showed that the highest compressive strength was observed in Group III (4,62±0,12 MPa), followed by Group II (4,59±0,11 MPa) and Group I (4,15±0,25 MPa). Kruskal–Wallis analysis revealed a statistically significant difference in compressive strength among all treatment groups (p < 0,05). It can be concluded that increasing the percentage of nano-hydroxyapatite relative to gelatin enhances the compressive strength of the scaffold.93 PagesSkripsi Sarjan
Comparative Study of Random Forest and Elastic Net Logistic Regression in Classifying Patient Discharge Status at BPJS Kesehatan Primary Healthcare Facilities: An Evaluation Based on F1-Score, PR AUC, and Brier Score
No full textThis study analyzes and compares the performance of Random Forest and Elastic Net Logistic Regression (SAGA solver) for classifying patient discharge status at BPJS Kesehatan Primary Care Facilities (FKTP). The dataset is large-scale, contains exclusively nominal predictors, and exhibits class imbalance (approximately 64.9% majority class). The experimental design employs an 80%/20% train–test split, one-hot encoding for preprocessing, and class balancing on the training data via random undersampling. Hyperparameter tuning is conducted using a staged coarse-to-fine search with local-optimum convergence criteria (improvement threshold ε = 10^(−6) and patience = 10), followed by 10-fold cross-validation for internal evaluation and final assessment on the test set. The primary evaluation metrics are F1-Score, Precision–Recall AUC (PR AUC), and Brier Score. On the test set, both methods achieve identical F1-Scores and nearly identical PR-AUC values. Random Forest and Elastic Net Logistic Regression both attain F1 = 0.996679, with PR-AUC = 0.999931 for Random Forest and 0.999927 for Elastic Net Logistic Regression. A more interpretable difference is observed in probability calibration, where Elastic Net Logistic Regression yields a lower Brier Score (0.002016) compared to Random Forest (0.002706). These results indicate that while both models lie on the same performance plateau in terms of discrimination and ranking, Elastic Net Logistic Regression provides better-calibrated probability estimates.144 PagesSkripsi Sarjan
Selection of Families Based on Flowering Age and Yield of Crosses Between Three Soybean [(Glycine max (L.) Merril)] parents
No full textKedelai merupakan sumber protein nabati yang penting di Indonesia, sering digunakan sebagai bahan pangan, pakan ternak, dan bahan baku industri. Namun, Indonesia masih sangat bergantung pada impor kedelai, yang menjadi masalah nasional. Oleh karena itu, penelitian ini bertujuan untuk meningkatkan produktivitas kedelai dalam negeri melalui pemilihan varietas unggul. Penelitian dilaksanakan dari Oktober 2024 hingga Januari 2025 di Jalan Pasar 1 Nomor 296, Tj. Sari, Kecamatan Medan Selayang, Provinsi Sumatera Utara, pada ketinggian 32 mdpl, dengan menggunakan metode analisis deskriptif. Hasil penelitian menunjukkan bahwa 24 galur tanaman terbaik terpilih berdasarkan karakter umur berbunga yang seragam antara 28-29 hari dan bobot biji tertinggi mencapai 45,52 gam. Uji T menunjukkan bahwa karakter fenotipik kedelai F5 lebih dominan menyerupai tetua Grobogan, yang mengindikasikan adanya pengaruh gen maternal dalam pewarisan sifat. Diferensial seleksi mengungkapkan peningkatan signifikan pada karakter bobot biji, sementara umur berbunga dan jumlah polong hampa relatif stabil, menandakan produksi kedelai yang optimal. Penelitian ini menyimpulkan bahwa seleksi famili F5 berhasil menghasilkan 24 galur dengan karakter umur berbunga yang lebih cepat dan bobot biji yang tinggi, sehingga berpotensi untuk menghasilkan varietas kedelai unggul yang dapat mendukung ketahanan pangan di Indonesia.53 PagesSkripsi Sarjan
IoT-Based Calorimeter Innovation for Deconstructing the Calorific Value of Oil Fuels Produced From Plastic Waste Pyrolysis
No full textThis study aims to design and develop an Internet of Things (IoT)-based calorimeter
system to measure the calorific value of pyrolysis oil fuel derived from plastic waste,
specifically high-density polyethylene (HDPE). This research was conducted to
overcome the limitations of conventional calorimeters by integrating digital sensors
and automation systems to improve measurement accuracy and efficiency. The system
was designed using a PT100 RTD temperature sensor with a MAX31865 module, an
INA219 current-voltage sensor, an ESP32 microcontroller, a relay, and an I²C LCD
for data display. Data acquisition and transmission were carried out through the Blynk
IoT platform, which enabled real-time monitoring and automatic storage to Google
Drive. This research was conducted at the LIDA Physics Laboratory of the University
of North Sumatra for five months. The device was calibrated using standard kerosene
fuel with an average temperature increase of 0.65°C to obtain the system's heat
capacity (Ckal) value. Validation tests were conducted using oil from HDPE plastic
pyrolysis. The test results showed average heat values of 7,766 cal/g, 7,435 cal/g, and
8,262 cal/g, with an overall average of 7,821 cal/g and an RSD value of 4.7%,
indicating good precision. The deviation from the reference value (10,936.73 cal/g)
was 28.5%, caused by heat loss and combustion variations. Overall, this IoT-based
calorimeter successfully demonstrated consistent, efficient, and accurate
measurements, making it suitable for analyzing the energy potential of alternative
fuels produced from plastic waste pyrolysis.88 pagesSkripsi Sarjan
Analysis of Factors Affecting the Volume of Banana Exports from North Sumatra to Malaysia
No full textBananas are one of Indonesia’s main horticultural commodities with high production volumes each year. One of the major banana-producing regions that plays an important role in exports, particularly to Malaysia, is North Sumatra Province. On the island of Sumatra, almost the entire volume of banana exports to Malaysia originates from this province. However, the contribution of exports to the total banana production in North Sumatra remains relatively low, indicating that export potential has not yet been optimally utilized. This study aims to analyze the factors affecting the volume of banana exports from North Sumatra to Malaysia during the period 2017–2024. The independent variables in this study are banana production in North Sumatra, the average export price (Free On Board/FOB) of bananas from North Sumatra to Malaysia, the Rupiah exchange rate against the US Dollar, inflation in Malaysia, and inflation in North Sumatra. This study uses quarterly secondary data and is analyzed using multiple linear regression with EViews 12 software. The results show that simultaneously all independent variables have a significant effect on the volume of banana exports from North Sumatra to Malaysia. Partially, the Rupiah exchange rate against the US Dollar and inflation in Malaysia have a significant effect on banana export volume.80 PagesSkripsi Sarjan
The Effect of Goat Manure and NPK Fertilizer on the Growth of Water Spinach (Ipomoea reptans Poir)
No full textWater spinach (Ipomoea reptans Poir) is one of the most popular leafy vegetables in Indonesia. In addition to being easy to cultivate, water spinach also has high nutritional value and is widely favored by people from various backgrounds. This vegetable contains various vitamins such as vitamins A and C, as well as essential minerals such as iron and calcium, which play an important role in maintaining body health. This study was conducted on farmland in Teluk Panji Village, Kampung Rakyat District, Labuhan Batu Selatan Regency, North Sumatra Province at an altitude of 25 meters above sea level from June 2025 to July 2025. The research used a two-factorial Randomized Block Design (RBD) with two treatment factors, namely: Factor 1: Goat manure fertilizer with four dosage levels: 0 g/plant, 30 g/plant, 60 g/plant, and 90 g/plant. Factor 2: NPK 15:15:15 fertilizer with three dosage levels 0 g/plant, 0.5 g/plant, and 1 g/plant. The observed variables included plant height, number of leaves, stem diameter, fresh shoot weight, fresh root weight, and total fresh plant weight.The application of goat manure fertilizer had a significant effect on plant height, number of leaves, stem diameter, fresh shoot weight, fresh root weight, and total fresh weight of water spinach. The application of NPK fertilizer had a significant effect on plant height, number of leaves, stem diameter, fresh shoot weight, fresh root weight, and total fresh weight of water spinach. The interaction between goat manure fertilizer and NPK had a significant effect on plant height, number of leaves, fresh shoot weight, fresh root weight, and total fresh weight of water spinach. However, the interaction between goat manure fertilizer and NPK had no significant effect on the stem diameter of water spinach plants.89 PagesSkripsi Sarjan
The Effect of Lignin Extracted from Oil Palm Empty Fruit Bunches (OPEFB) as a Green Corrosion Inhibitor on ST 41 Steel in Sulfuric Acid Media
No full textThis research was conducted to investigate the effect of inhibitor concentration and immersion time on weight loss, corrosion rate, inhibition efficiency, and surface roughness variation of low-carbon steel ST 41. The study also aimed to evaluate the inhibition efficiency of lignin extracted from Oil Palm Empty Fruit Bunches (EFB) in reducing the corrosion rate of ST 41 steel and to analyze the morphological characteristics of the steel surface both with and without the inhibitor. The weight loss method was employed as the primary technique, as it is the simplest approach to determine the corrosion rate by comparing the initial weight of the specimen to its weight after immersion in the inhibitor solution. Morphological characterization and identification of the corrosion type were carried out through microscopic and cross-sectional observations. The results showed corrosion rate values of 31.6922 mpy, 24.8851 mpy, and 19.7146 mpy, corresponding to inhibition efficiencies of 34.56%, 53.93%, and 79.305% for the 3 g/L inhibitor concentration at immersion times of 1 hour, 3 hours, and 6 hours, respectively. Meanwhile, at a concentration of 7 g/L, the corrosion rates were 26.3358 mpy, 20.3842 mpy, and 15.9577 mpy, with inhibition efficiencies of 45.62%, 62.26%, and 83.24% for the same immersion durations. The adsorption behavior of the inhibitor on ST 41 steel was evaluated using the Langmuir adsorption isotherm model, which indicated that the dominant adsorption mechanism was physisorption.126 pagesSkripsi Sarjan
Effect of Lemongrass Essential Oil (Cymbopogon nardus) as an Alternative Solvent on Epoxy Resin Sealer Cleanliness of Root Canal Walls during Endodontic Retreatment (In Vitro)
No full textEndodontic retreatment requires the use of solvents to assist in the removal of
old obturation materials, including epoxy resin sealers that adhere strongly to root canal
walls. This study aimed to evaluate the effect of citronella essential oil (Cymbopogon
nardus) on the cleanliness of epoxy resin sealer on root canal walls during in
vitro endodontic retreatment. This in vitro experimental study with a post-test only
design used mandibular premolars divided into three groups: no solvent, orange oil,
and citronella essential oil. Root canal wall cleanliness was evaluated using a
stereomicroscope and analyzed quantitatively. The results demonstrated significant
differences in root canal wall cleanliness among the groups, with the orange oil group
showing the highest level of cleanliness, followed by the lemongrass essential oil
group, while the no-solvent group exhibited the lowest level. It can be concluded that
lemongrass essential oil contributes to improving the cleanliness of root canal walls
from epoxy resin sealer residues, although its effectiveness remains inferior to that of
orange oil.122 PagesSkripsi Sarjan