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Kajian Pembuatan Oksida Grafit untuk Produksi Oksida Grafena dalam Jumlah Besar (Halaman 26 s.d. 29) Norman Syakir; Rhesti Nurlina; Syafiul Anam; Annisa Aprilia; Sahrul Hidayat; Fitrilawati -
Jurnal Fisika Indonesia Vol 19, No 56 (2015)
Publisher : Department of Physics Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (448.608 KB) | DOI: 10.22146/jfi.24354

Abstract

Oksida grafit (GO) telah berhasil disintesis menggunakan metode Hummers dari serbuk grafit dengan pelarut asam sulfat (H2SO4), natrium nitrat (NaNO3), kalium permanganat (KMnO4), dan hidrogen peroksida (H2O2).  Hasil sintesis berupa pasta dicuci dengan asam klorida (HCl) dan akuades berulang-ulang untuk mendapatkan GO yang relatif murni.  Pasta tersebut selanjutnya dikeringkan dan digerus untuk karakterisasi EDS (Energy Dispersive Spectroscopy), difraksi XRD (X-ray Difraction), dan spektroskopi FTIR (Fourier Transform Infrared).  Untuk mengupas lembaran GO menjadi lapisan lebih tipis, pasta yang dihasilkan tersebut didispersikan dalam akuades, kemudian disonikasi serta disentrifugasi.  Hasil yang didapat dikarakterisasi dengan menggunakan spektroskopi UV-Vis.  Hasil karakterisasi sampel serbuk menunjukkan telah terjadi perubahan struktur grafit dengan terbentuknya gugus-gugus fungsional oksigen.
KARAKTERISTIK TRANSPARANSI FILM TIPIS OKSIDA GRAFENA TEREDUKSI (R-GO) UNTUK ELEKTRODA TRANSPARAN DERI LASMANA; GIYA PRANATA; RHESTI NURLINA; ANNISA APRILIA; NORMAN SYAKIR; FITRILAWATI F
Jurnal Material dan Energi Indonesia Vol 6, No 01 (2016)
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (376.269 KB) | DOI: 10.24198/jmei.v6i01.11144

Abstract

Grafena adalah material karbon dua dimensi yang mempunyai sifat optik dan listrik yang menarik sehingga memiliki banyak potensi aplikasi, diantaranya elektroda transparan. Grafena dapat diperoleh melalui proses reduksi termal dari Oksida Grafena (GO) yang dikenal sebagai Oksida Grafena Tereduksi (r-GO). Film tipis GO dibuat dari 4 mg/ml suspensi GO pada substrat quartz dengan metode spin coating. Film tersebut selanjutnya dikenakan proses reduksi secara termal melalui pemanasan dalam oven yang dialiri dengan gas nitrogen. Pengaruh proses reduksi termal terhadap transparansi dan struktur GO diukur dengan spektroskopi UV-Vis dan SEM-EDS (Scanning electron microscope-Energy Dispersive Spectroscopy). Hasil pengukuran spektrum UV-Vis menunjukkan adanya perubahan transparansi dan peningkatan absorbsi seiring dengan penambahan waktu pemanasan. Perubahan transparansi pada sampel GO yang dikenakan proses reduksi termal mencapai keadaaan saturasi setelah pemanasan sekitar 150 menit. Di lain pihak, hasil pengukuran EDS menunjukkan adanya peningkatan rasio C/O pada pada sampel GO setelah dikenakan proses reduksi termal akibat berkurangnya kadar oksigen. Pengurangan kadar oksigen tersebut mengindikasikan adanya pemulihan konjugasi pada rantai karbon sehingga meningkatkan absorbansi dan juga diharapkan dapat meningkatkan konduktivitas.
Kajian Penggunaan Sensor dalam Sistem Pengujian dan Pemantauan Kualitas Air Minum Layak Konsumsi Suhanto, Rhesti Nurlina
Polygon : Jurnal Ilmu Komputer dan Ilmu Pengetahuan Alam Vol. 3 No. 1 (2025): Polygon : Jurnal Ilmu Komputer dan Ilmu Pengetahuan Alam
Publisher : Asosiasi Riset Ilmu Matematika dan Sains Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62383/polygon.v3i1.396

Abstract

The human body cannot work properly without water. Therefore, it is essential to conduct testing and monitoring of drinking water quality to ensure its safety and suitability for consumption. This has prompted researchers to develop more efficient systems compared to traditional methods. This study employs a systematic literature review approach by analysing various published articles to identify and evaluate the application of different types of sensors capable of detecting physical and chemical parameters for assessing drinking water quality. The findings indicate that the integration of sensors, microcontrollers, and Internet of Things (IoT) technology can provide accurate data that is accessible in real-time and remote locations. Furthermore, to enhance the reliability of the system, it is necessary to further develop data processing algorithms by applying artificial intelligence (AI) and/or machine learning technique to create smart systems with improved predictive capabilities. The implementation of these technologies is expected to support the Indonesian government’s Sustainable Development Goals (SDGs) by providing safe and affordable access to drinking water for all its citizens.
Edukasi Kualitas Air Minum Yang Aman Bagi Mahasiswa Suhanto, Rhesti Nurlina; Westari, Dwianti; Ilman, Syaeful
Lamahu: Jurnal Pengabdian Masyarakat Terintegrasi Vol 4, No 1: February 2025
Publisher : Universitas Negeri Gorontalo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37905/ljpmt.v4i1.30085

Abstract

The quality of drinking water is a critical factor that impacts an individual's health. Contaminated drinking water can serve as a medium for disease transmission and lead to the decline in organ function. The lack of public awareness about the standards for safe drinking water has prompted educational initiatives for the students of Instrumentation and Control Engineering Technology program at Politeknik Negeri Indramayu. This initiative included a presentation, interactive discussions, and an evaluation. Following their participation, most students gained a better understanding of the criteria for safe drinking water and became more aware of the importance of monitoring water quality. They also expressed interest in developing technologies to detect drinking water quality as an innovative solution for public health. Furthermore, implementation of this activity is expected to accelerate the adoption of drinking water quality monitoring technologies, ultimately reducing the risk of waterborne diseases.
Perancangan dan Pengujian Sistem Pendingin untuk Pengolahan Cokelat Pasca-Tempering Suhanto, Rhesti Nurlina; Fatwasauri, Icha; Dharmawan Hadi, Bagus; Septyansyah
Malikussaleh Journal of Mechanical Science and Technology Vol. 9 No. 1 (2025): Malikussaleh Journal of Mechanical Science and Technology (MJMST)
Publisher : Malikussaleh University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29103/mjmst.v9i1.21509

Abstract

The post-tempering cooling process in chocolate production is critical for achieving the desired quality attributes, including gloss, texture, and the stability of cocoa butter crystals. An essential aspect of the food processing industry is the demand for reliable cooling systems to maintain product quality, particularly in chocolate processing. This research focuses on designing and evaluating a cooling system based on an air cooled mini chiller integrated with an Air Handling Unit (AHU). The system gradually lowers the temperature of chocolate from 50°C to 27°C. The process involves creating a system based on cooling load calculations and thermal efficiency analysis, assembling it with a thermally insulated cabin, and conducting experimental testing to evaluate its performance. The testing environment was maintained at 31°C with relative humidity between 70% and 80%, without the use of a dehumidification system. The result indicates that the system can reduce the product temperature to 27°C in 38 minutes, with an efficiency of 63%. This represents an improvement compared to initial design efficiency, which was only 52%. Moreover, the cooling system operates effectively and stably, making it suitable for application in small-scale chocolate processing industries with a production capacity of 1–5 kg per cycle. This innovative solution is effective, stable, energy-efficient, and tailored for small scale chocolate production, and also offers future advancements in automated cooling technologies.
PENGEMBANGAN KENDALI MESIN PENDINGIN COKELAT BERBASIS NODEMCU Rhesti Nurlina Suhanto; Icha Fatwasauri; Indra Fitriyanto; Arya Maulana Syah Putra
TESLA: Jurnal Teknik Elektro Vol 27 No 1 (2025): TESLA: Jurnal Teknik Elektro
Publisher : Universitas Tarumanagara

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24912/tesla.v27i1.33966

Abstract

The control system in refrigeration machines is crucial in maintaining operational efficiency and product quality, particularly in the food industry, where precise temperature control is essential. Manual operation of refrigeration machines at production sites often limits the flexibility and effectiveness of the cooling process. This study aims to design and implement a mini chocolate refrigeration control system based on NodeMCU, connected via WiFi. The proposed system allows the machine to be operated manually through physical push buttons or remotely via a web page displaying real-time updates on the machine's operational status. The research methodology involves designing the control circuit, assembling all components into a control panel box, testing the system in two operational modes, and evaluating the refrigeration performance. The results indicate that the control system operates responsively and accurately in manual and remote modes. The web page accurately displays the machine's actual conditions on-site. The cooling patterns generated by the refrigeration system demonstrate its ability to effectively support the chocolate crystallization process, thus producing high-quality chocolate products. In conclusion, the Internet of Things (IoT)-based control system effectively enhances flexibility and efficiency in the cooling process within small and medium-scale food processing industries, with the potential to improve product quality and overall productivity. Abstrak Sistem kendali pada mesin pendingin memegang peranan penting dalam menjaga efisiensi operasional dan kualitas produk, khususnya dalam industri makanan yang memerlukan kontrol suhu yang presisi. Pengoperasian mesin pendingin yang masih bergantung pada kontrol manual di lokasi produksi sering kali membatasi fleksibilitas dan efektivitas proses pendinginan. Penelitian ini bertujuan untuk merancang dan mengimplementasikan sistem kendali mesin pendingin cokelat skala kecil berbasis NodeMCU yang terhubung melalui jaringan WiFi. Sistem yang dikembangkan memungkinkan pengoperasian mesin secara manual melalui tombol tekan maupun jarak jauh melalui halaman web yang menampilkan status operasional mesin secara real-time. Metode yang digunakan meliputi perancangan rangkaian kontrol, perakitan seluruh komponen ke dalam kotak panel, dan pengujian kendali sistem dalam dua mode serta pengujian sistem pendinginan. Hasil menunjukkan bahwa sistem bekerja dengan responsif dan akurat dalam kedua mode. Halaman web mampu menampilkan kesesuaian dengan kondisi aktual mesin di lapangan. Pengujian sistem pendinginan memperlihatkan pola penurunan temperatur yang menunjukkan kemampuan sistem dalam mendukung proses kristalisasi cokelat secara optimal, sehingga dapat menghasilkan produk cokelat dengan kualitas baik. Dapat simpulkan bahwa sistem kendali berbasis Internet of Things (IoT) ini efektif diterapkan untuk meningkatkan fleksibilitas dan efisiensi proses pendinginan pada industri pengolahan makanan berskala kecil dan menengah, serta berpotensi meningkatkan kualitas dan produktivitas produksi secara keseluruhan.