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All Journal Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Jurnal Sains Materi Indonesia
Warmiati
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ANALYSIS OF WATER ABSORPTION AND TOTAL CHROME LEACHING TEST USING ATOMIC ABSORPTION SPECTROPHOTOMETER (AAS) ON PAVING BLOCK SAMPLES MADE FROM WASTE LEATHER SHAVING Warmiati; Septiyana Windiastuti
Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Vol 22 No 2 (2023): Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit
Publisher : Politeknik ATK Yogyakarta

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Abstract

Shaving waste from leather tanning can be utilized as a filler material in the production of concrete blocks. The manufactured concrete blocks are subsequently subjected to immersion for durations of 1, 3, 7, 10, and 14 days. Subsequently, the leached total chromium content from the soaked concrete blocks is tested using an atomic absorption spectrophotometer, by the Indonesian National Standard (SNI) 6989-84:2019, which outlines the procedure for testing dissolved and total metal content through atomic absorption spectrometry. Additionally, water absorption testing is conducted according to SNI 03-0349:1989 for concrete blocks used in wall construction. The aim of this research is twofold: to determine the water absorption capacity of three sample variations and compare the results against the SNI, and to ascertain the leached chromium concentration from the soaked blocks over a time range of 1 to 14 days, using an atomic absorption spectrometer and referring to the established environmental quality standards. The results obtained from testing the total chromium content released from the soaked concrete blocks meet the requirements of the quality standards for chromium content in leather tanning wastewater, as specified in Ministerial Regulation No. 5 of 2014 (maximum of 0.6 mg/L) and Local Regulation of Yogyakarta Special Region No. 7 of 2016 (maximum of 0.5 mg/L). Meanwhile, the water absorption testing outcomes for the concrete block samples derived from shaving waste comply with the stipulations of SNI 03-0349:1989. Sample codes A and B meet the criteria for quality level 1, with a maximum absorption of 25%, while sample code C meets quality level II standards.
LABORATORY SCALE OF RAYON FIBER MANUFACTURING: MANUAL STIRRING AND STIRRING USING A MAGNETIC STIRRER Dewi Nurhidayati; Warmiati; Wijayanti
Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Vol 23 No 1 (2024): Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit
Publisher : Politeknik ATK Yogyakarta

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Laboratory scale production of rayon fiber has been carried out using manual stirring and a magnetic stirrer. The aim of this research is to compare rayon fiers produced through manual stirring and magnetic stirrer stirring. Experiments on making rayon on a laboratory scale are carried out for educational purposes which often have obstacles due to the limited availability of mixing equipment, such as magnetic stirrer. The method used in making rayon in this research is through the formation of cuprammonium ions. The results show that there is no significant difference between rayon produced manual stirring and magnetic stirrer stirring. It means that the manual mixing can be applied in the learning process for making rayon due in order to get around the limitations of available mixing equipments.
MOISTURE CONTENT MEASUREMENT IN GELATIN: A COMPARISON OF GRAVIMETRIC METHODS USING MOISTURE ANALYZER AND OVEN Warmiati; Dewi Nurhidayati
Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Vol 23 No 1 (2024): Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit
Publisher : Politeknik ATK Yogyakarta

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The measurement of water content in gelatin samples in the practical activities in the Instrumentation and Polymer Engineering Laboratory is conducted using the gravimetric method with the Moisture Analyzer Sartorius Type MA 45. Meanwhile, the method acknowledged and approved by AOAC International is the Oven method. This research aims to compare the measurement results of the Moisture Analyzer with the reference method, namely the Oven method referring to AOAC, to determine if there is a statistically significant difference in the results. The results of both methods are compared using a paired T-test, yielding a calculated T-value (Tstat) of 0.7519 and a tabulated T-value of 2.2622. These results indicate that Tstat ≤ the tabulated T-value at a 95% confidence level, thus accepting the null hypothesis (H0). This suggests that μa=μb, meaning that there is no significant difference between the two methods. The precision test results for both methods also meet the criteria, with %RSD ≤ 2% and %RSD ≤ 2/3 CV Horwitz.
ANALYSIS OF METAL CONTENTS IN WELL WATERAT THE ATK YOGYAKARTA POLYTECHNIC LABORATORY Warmiati; Wijayanti; Armila Zahra Tawarniate; Dewi Nurhidayati
Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Vol 23 No 1 (2024): Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit
Publisher : Politeknik ATK Yogyakarta

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This sudy has been conducted to determine the metal content in water used for laboratory activities at Politeknik` ATK Yogyakarta. The water used for laboratory processes should ideally be free from metal content to avoid contamination and corrosion. The metal content analyzed in this research includes Cu, Pb, Cr, adn Fe. The analysis method used is spectrophotometry, specifically Atomic Absoprtion Spectrophotometry (AAS), using standard series. The samples to be analyzed are first destructed according to the method outlined in SNI 6989 – 84: 2019. The analysis results obtained are as follows: Cu content in water sample is 0.046 mg/L, Pb content is 3.031 mg/L, Cr metal is 0.023 mg/L, and Fe content is 6.372 mg/L.
Study of the Effect of Ultraviolet Exposure Duration on Polypropylene Properties Saputra, Andri; Sitinjak, Tria Madeline; Warmiati; Hermiyati, Indri; Ratnaningsih, Wahyu; Hariyadi, Asful; Nurry, Dennis Farina
Jurnal Sains Materi Indonesia Vol. 27 No. 1 (2025): Jurnal Sains dan Materi Indonesia
Publisher : BRIN Publishing (Penerbit BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/jsmi.2025.8959

Abstract

Prolonged exposure to ultraviolet (UV) radiation significantly alters the chemical, thermal, and mechanical properties of polypropylene (PP), leading to degradation and reduced material performance. This study aims to investigate the effect of exposure length to UV on the chemical properties (functional and thermal) and mechanical properties (tensile strength) of PP. Specimens were subjected to UV exposure for 0 (control), 125, 175, 225, 275, 325, 375, and 625 days. FTIR analysis indicates UV exposure chemically degrades polypropylene (PP) by generating new oxygenated groups (–OH and C=O at 3368 cm⁻¹ and 1586 cm⁻¹) and damaging its main molecular structure (C-H at 2949 cm⁻¹, 2867 cm⁻¹, and 841 cm⁻¹). Prolonged UV exposure alters the thermal properties of polypropylene (PP), as indicated by DSC analysis, which shows broadening and shifting of the melting peak (175–180 °C) due to crystallinity changes and increased oxidation. The mechanical properties also deteriorate, with a critical reduction in tensile strength, particularly between 225 and 375 days, indicating an accelerated degradation phase. After 625 days, tensile strength declines by approximately 59%, confirming the substantial impact of extended UV exposure on PP’s durability.
Co-Authors Andri Saputra Armila Zahra Tawarniate Dewi Nurhidayati Hariyadi, Asful Hermiyati, Indri Nurry, Dennis Farina Ratnaningsih, Wahyu Septiyana Windiastuti Sitinjak, Tria Madeline Wijayanti