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All Journal BERKALA SAINSTEK Rekayasa Mesin Eksergi: Chemical Engineering Journal Jurnal Rekayasa Material, Manufaktur & Energi SELAPARANG: Jurnal Pengabdian Masyarakat Berkemajuan Menara: Jurnal Teknik Sipil Jurnal Inovasi Pendidikan dan Sains Journal of Biobased Chemicals (JOBC) Jurnal Pengabdian Pada Masyarakat Warta LPM Jurnal Teknologi Kimia Mineral
Ratri Sekaringgalih
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IMPROVED HARDNESS AND CORROSION BEHAVIOUR OF ALUMINIUM 6061 ALLOY THROUGH ECAP PROCESSING Sekaringgalih, Ratri; Putrayasa, I. Nyoman Gede; Puspasari, Vinda; Wardono, Joko Tri; Yustisia, Ari; Ari Kurniawan
Jurnal Rekayasa Mesin Vol. 16 No. 2 (2025)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/jrm.v16i2.1524

Abstract

The study was done to evaluate the effect of equal channel angular pressing (ECAP) processing on the hardness, optical morphology, and corrosion behavior of Al-6061 alloy. The samples were first annealed, and continued with ECAP process using the Bc route at 120° of internal channel angle with variation of passes (one, two, three, and four). The examination of corrosion resistance of Al-6061 alloy was examined using open circuit potential measurement, tafel polarization, and cyclic polarization. Moreover, the morphology of Al-6061’s surface after corrosion test was also studied using an optical microscope. The hardness test increased gradually with the addition of pass number in ECAP processing from 48.60 HB (0-pass) to 110.8 HB (4-passes). ECAP processing affects the microstructure of Al-6061 alloy, where the elongated grains are aligned parallel to the extrusion direction. Furthermore, the grain size of samples with higher pass numbers is more homogeny than samples with lower pass numbers. Meanwhile, the Tafel Polarization curves showed that ECAP processing in all samples decreased the corrosion rate from 0.6263 mmpy (as-annealed sample) to 0.1508 mmpy (4-passes sample). This phenomenon reveals that the corrosion resistance of Al-6061 alloy samples raises by the existence of ECAP processing. According to the morphological observation of Al-6061 samples, grain refinement due to ECAP processing could improve corrosion resistance.
BIOETHANOL FROM CHEESE WASTE (WHEY) USING KLUYVEROMYCES MARXIANUS Alif Nur Laili Rachmah; Ratri Sekaringgalih; Binti Ruliana; Ansori Ansori
Jurnal Inovasi Pendidikan dan Sains Vol 4 No 3 (2023): December
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat Universitas Nahdlatul Wathan Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51673/jips.v4i3.1799

Abstract

Alternatives to petroleum scarcity are of much concern to researchers. The development of bioethanol is one of the renewable energies that must be supported by research from various sources of raw materials so that it can be converted into bioethanol. Generally, the raw material of bioethanol used contains sugar and starch. if biomass used sugar cane and cassava then the availability of food will also be threatened. Therefore one of the alternative raw materials that can be used is industrial waste cheese (whey). Whey is the side of the product cheese industry, which contains 4-5%. The aim of the study is to optimate whey fermentation to the production of bioethanol using Kluyveromyces marxianus with the variation of time and starter volume. Bioethanol production with raw material lactose which is contained in whey used Kluyveromyces Marxianus with variabel changed time fermentation and starter volume. For time fermentation variables are 24, 48, 60, 72 dan 84 hours, and for volume starter variabel are 20%, 22%, dan 24% v/v. The highest content of bioethanol production used Kluyveromyces Marxianus on variable starter volume 24% at time 84 hours was obtained 0,32% bioethanol content with pH 3,5
Extraction of Bioactive Compounds from Coffee Husk with Acetone Using Microwave Assisted Extraction Method and Analysis of Phenolic Compounds Theressa Julieta Putri Andina; Helda Wika Amini; Ansori Ansori; Yukti Nurani; Ratri Sekaringgalih; Sonya Hakim Raharjo; Merymistika Yufrani Afred
JOBC Vol. 4 No. 2 (2024): Journal of Biobased Chemicals
Publisher : University of Jember

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Abstract

. Nowadays, coffee husks are limited to animal feed and fertilizer. Therefore, a study used Robusta coffee husk waste as a raw material. The purpose of this study was to determine the effect of several variables and to determine the optimum conditions in the process of extracting bioactive compounds from coffee husk waste. The coffee husk contains bioactive compounds, including anthocyanins and polyphenol compounds, such as flavonols, flavan-3-ols, hydroxycinnamic acids, and caffeine. Coffee husk waste will be extracted using the Microwave-Assisted Extraction (MAE) method with acetone solvent, with several variables: the ratio of material to solvent, microwave power, and extraction time. Analysis of the identification of phenolic compound content was then also carried out using UV-Vis spectrophotometry. The variables of material ratio, extraction time, and microwave power were proven to be interrelated so that they could produce total phenol at optimum conditions. The optimum conditions for extracting bioactive compounds from coffee husk waste were obtained at a material ratio of 0.04 g/mL, 9 minutes, and power of 300 watts, with a total phenol yield of 8.65 GAE/g sample.
Process Optimization for Bioplastic Synthesis from Ulva Lactuca with the Addition of Citric Acid and Boric Acid as Crosslinkers Yukti Nurani; Hilda Huril Ainia; Alfun Ni’matil Husna; Sonya Hakim Raharjo; Merymistika Yufrani Afred; Ansori Ansori; Ratri Sekaringgalih; Helda Wika Amini; Ditta Kharisma Yolanda Putri; Meta Fitri Rizkiana; Boy Arief Fachri; Zuhriah Mumtazah; Istiqomah Rahmawati; Bekti Palupi; Felix Arie Setiawan
BERKALA SAINSTEK Vol. 14 No. 2 (2026)
Publisher : University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/bst.v14i2.60021

Abstract

The development of renewable biomass-based bioplastics is one solution to reduce environmental pollution caused by the use of conventional petroleum-based plastics. One potential source of biomass is Ulva lactuca, which contains ulvan polysaccharides that can be used as a material for forming biodegradable bioplastic films. This study aims to determine the optimum conditions for the synthesis of ulvan-based bioplastics using the Response Surface Methodology (RSM). Bioplastics were synthesized using the solution casting method with ulvan filtrate as the main matrix and polyvinyl alcohol (PVA) as the supporting polymer, with glycerol and sorbitol as plasticizers and citric acid and boric acid as cross-linkers. Optimization was performed using a Box–Behnken design with 17 experiments, with independent variables of boric acid mass (0.025 - 0.075 g), mixing temperature (65 - 75 ˚C), and mixing time (15 - 25 minutes). The optimization results showed that optimal conditions at a mixing temperature of 70 °C, boric acid mass of 0.05 g, and mixing time of 20 minutes, with point prediction of 4.1476 MPa in tensile strength, thickness of 0.088 mm, and desirability value of 1. The statistical model for tensile strength demonstrated an R2 value of 0.9468, an adjusted-R2 of 0.8785, and a lack-of-fit value of 0.3024. Meanwhile, the thickness model exhibited an R2 value of 0.9792, an adjusted-R2 of 0.9524, and a lack-of-fit value of 0.7510.
Co-Authors Afred, Merymistika Yufrani Alfun Ni’matil Husna Alif Nur Laili Rachmach Alif Nur Laili Rachmah ansori ansori Ansori Ansori Ansori Ansori Ari Kurniawan Ayu Qurota A’yun Bekti Palupi Binti Ruliana Boy Arief Fachri Ditta Kharisma Yolanda Putri Felix Arie Setiawan Gessantara, M. Febbia Helda Wika Amini Hilda Huril Ainia Indahma Puji Lestari Istiqomah Rahmawati Julieta, Theressa Meta Fitri Rizkiana Nabila Salsabila Hanum Nurul Hidayati Puspasari, Vinda Putrayasa, I. Nyoman Gede Sonya Hakim Raharjo Syaifullah, Rangga Yudha Theressa Julieta Putri Andina Wardono, Joko Tri Yohanes Yukti Nurani Yuni Susanti Yustisia, Ari Zuhriah Mumtazah