Garuda - Garba Rujukan Digital

p-Index From 2021 - 2026

1.347

P-Index

This Author published in this journals

All Journal Microbiology Indonesia Seminar Nasional Teknik Kimia Kejuangan Jurnal Zeolit Indonesia Jurnal RESTI (Rekayasa Sistem dan Teknologi Informasi) Neo Teknika: Jurnal Ilmiah Teknologi Journal of Data Science and Its Applications Jurnal SUBLIMAPSI CENDEKIA: Jurnal Ilmiah Pendidikan Aceh International Journal of Science and Technology Jurnal Kendali Akuntansi Metalurgi

Widi Astuti

Unknown Affiliation

Author-ID : 415342

Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Engineering Environmental Science Immunology & microbiology Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Mathematics Medicine & Pharmacology Social Sciences Other

Published : 23 Documents Claim Missing Document

Claim Missing Document

Articles

1 2 3

BLEACHING OF CRUDE PALM OIL BY ADSORPTION METHOD WITH USING NATURAL ZEOLITE FROM LAMPUNG Widi Astuti; Muhammad Amin; Aprimal Aprimal
Jurnal Zeolit Indonesia Vol. 5 No. 2 (2006)
Publisher : Jurnal Zeolit Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar

The research about bleaching of crude palm oil by adsorption method with using natural zeolite from Lampung has been done. The experiment result shows that natural zeolite from Lampung can be used as adsorbent for bleaching process of crude palm oil. Zeolite had been activated by chemical method with hydrochloric acid (HCl) solution before it was used as adsorbent. From the experiment result, we know that the best condition for bleaching process are weight percentage of zeolite that was used to get the highest of transmittance is 20% and the best concentration of HCl solution is 4%. The highest of transmittance for this condition is 48.5.

DESALINATION OF THE BRACKISH WATER USING SURFACTANT MODIFIED ZEOLITE (SMZ) Widi Astuti; Adil Jamali; Muhammad Amin
Jurnal Zeolit Indonesia Vol. 6 No. 1 (2007)
Publisher : Jurnal Zeolit Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar

The intrusion of seawater in the beach area of Bandar Lampung and the Eastern beach of Lampung causes many problems for people because it turns the water into a brackish water. The brackish water is the water whose salinity is between 0.5 ppt until 17 ppt. The brackish water cannot be used for drinking, cooking or washing because the maximum degree of salinity for such purposes is 0.5 ppt. Desalination of brackish water is a process of reducing the salinity of a brackish water. In this research, natural zeolite from Lampung was modified with surfactant to become surfactant-modified zeolite (SMZ). It was used as ion exchanger in the desalination of a brackish water. The result showed the salinity of the brackish water could be reduced to 52% from the initial value. The best results were obtained at the contact time of 4 hours and the initial salinity 0.863 ppt.

Implementation of Enhance Confix Stripping Stemmer Algorithm for Multiclass Dataset Classification in News Text using K-Nearest Neighbor Alvianda Ricky Lukman; Widi Astuti
Journal of Data Science and Its Applications Vol 4 No 1 (2021): Journal of Data Science and Its Applications
Publisher : Telkom University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.34818/jdsa.2021.4.76

Needs for news information has increased since the change from physical media to online media. News is grouped according to categories to making it easier for readers to get the news as desired. Grouping to determine the category of news information is known as text classification. The number of words in the news text create diversity of words that appear and can be minimized by the stemming process, which is changing an affixed word into its root word. This study comparing between use of stemming and without stemming and finding the best value of K and optimum distance calculation of K-Nearest Neighbor. The best accuracy is 0.9671 which is obtained when stemming algorithm not applied, number of K=9 and cosine distance is used as distance metric. This result is greater than the classification that applies stemming algorithm in condition K=7 using cosine distance which resulted accuracy in 0.9660.

Prediction of Retweets Based on User, Content, and Time Features Using EUSBoost Ghina Khoerunnisa; Jondri; Widi Astuti
Jurnal RESTI (Rekayasa Sistem dan Teknologi Informasi) Vol 6 No 3 (2022): Juni 2022
Publisher : Ikatan Ahli Informatika Indonesia (IAII)

Twitter is one of the popular microblogs that allow users to write posts. Retweeting is one of the mechanisms for the diffusion of information on Twitter. One way to understand the spread of information is to learn about retweet predictions. This study focuses on predicting retweets using Evolutionary Undersampling Boosting (EUSBoost) based on user, content, and time-based features. We also consider the vector of text as a predictive feature. Models with EUSBoost are able to outperform models using the AdaBoost method. The evaluation results show that the best model can achieve an AUC performance score of 77.21% and a GM score of 77.18%. While the Adaboost-based models achieved AUC scores ranging from 68% to 69% and GM scores ranging from 62% to 63%. In addition, we found that there was no significant difference between using numeric features only and combining numeric and text features.

Perbedaan Orientasi Masa Depan Terkait Pernikahan Pada Wanita Yang Bekerja Dan Wanita Tidak Bekerja Widi Astuti; Siska Siska; Rini Julistia
Jurnal Sublimapsi Vol 4, No 1 (2023): Jurnal Sublimapsi
Publisher : Jurusan Psikologi FKIP Universitas Halu Oleo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36709/sublimapsi.v4i1.35306

Penelitian ini bertujuan untuk mengetahui perbedaan orientasi masa depan terkait pernikahan pada wanita bekerja dan wanita tidak bekerja. Penelitian ini menggunakan pendekatan kuantitatif dengan jenis komparatif. Analisis yang digunakan dalam penelitian ini menggunakan uji-t untuk melihat apakah ada perbedaan orientasi masa depan terkait pernikahan pada wanita bekerja dan wanita tidak bekerja. Penelitian ini menggunakan teknik non probability sampling. Jumlah subjek dalam penelitian ini adalah tujuh ratus lima puluh lima orang wanita wanita bekerja dan wanita tidak bekerja. Hasil penelitian terdapat perbedan orientasi masa depan terkait pernikahan pada wanita bekerja dan wanita tidak bekerja dilihat berdasarkan hasil uji hipotesis 0,031. Terdapat selisih nilai yang terlihat ialah dimana wanita bekerja berkategori rendah sedangkan wanita tidak bekerja berkategori tinggi. Hal tersebut dikarenakan wanita bekerja walaupun sudah memiliki pasangan tetap saja menganggap pernikahan bukanlah prioritas utama dalam hidupnya. Sedangkan, Wanita tidak bekerja walaupun belum memiliki pasangan tetapi mereka sudah memiliki gambaran akan pernikahan nantinya.

ZnO Production from EAF Solid Waste Using Hydrothermal Methods via Oxalate Precipitation Lukman Nulhakim; Imam Prasetyo; Monna Rozana; Widi Astuti
Aceh International Journal of Science and Technology Vol 12, No 1 (2023): April 2023
Publisher : Graduate Program of Syiah Kuala University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13170/aijst.12.1.29579

Electric Arc Furnace (EAF) waste contains 50-60% Zn. EAF waste synthesis has the potential to produce ZnO, which can be used in a variety of applications. The hydrothermal method is used in the synthesis, with time variations of 3 and 6 hours and temperature variations of 120 °C, 150 °C and 200 °C using precipitating reagents in the form of sodium hydroxide (NaOH) and oxalic acid (C2H2O4). UV-Vis spectrophotometer characterization result shows the absorbance value at 365 nm, which is the absorbance characteristic of ZnO material. The result of increasing the Zn element was revealed by XRF characterization. The XRD characterization revealed zinc oxalate dehydrates. This result depicts the hydrothermal with the oxalic acid solvent used to produce zinc oxalate dehydration at various temperatures and time variations.

ANALISIS KINERJA KEUANGAN PADA PERUSAHAAN PDAM Widi Astuti; Eko Wahyuni
Jurnal Kendali Akuntansi Vol. 1 No. 1 (2023): Januari : Jurnal Kendali Akuntansi
Publisher : Universitas Katolik Widya Karya Malang

Pemerintah memperbaiki kondisi hidup masyarakat baik dari bidang sosial, ekonomi, maupun pelayanan dengan taraf peningkatan hidup melalui pembangunan nasional. Kebijakan pemerintah dalam pembangunan nasional yang telah terprogram diantaranya peningkatan sarana air bersih, menyediakan air bersih bersih dan terjamin secara merata kepada semua lapisan masyarakat. Pemerintah mendirikan Perusahaan Air Minum melalui Undang-Undang No. 5 tahun 1962 tanggal 14 Pebruari 1962 tentang Perusahaan Daerah, merupakan badan usaha yang harus menjalankan dua fungsi sekaligus, yaitu sebagai social oriented dan profit oriented. PDAM harus menjalankan kegiatan perusahaan dengan baik terutama peningkatan kinerja perusahaan. Sony Yuwono (2003:23) penilaian kinerja merupakan tindakan yang dilakukan dari berbagai aktifitas dalam rantai nilai yang ada dalam perusahaan

KARAKTERISTIK STRUKTUR MIKRO DAN SIFAT MEKANIK BESI TUANG PUTIH PADUAN KROM TINGGI HASIL THERMAL HARDENING UNTUK APLIKASI GRINDING BALL[Microstructure Characteristic and Mechanical Properties of Thermal Hardened of High Chromium White Cast Iron for Grinding Ball Application] Achmad Sofi; Widi Astuti; Fajar Nurjaman
Metalurgi Vol 28, No 3 (2013): Metalurgi Vol.28 No.3 Desember 2013
Publisher : National Research and Innovation Agency (BRIN)

Pembuatan Refraktori Dari Refraktori Bekas Pakai Kiln Dan Flyash Batubara Dengan Variasi Tekanan Greenbody [Recycling of Used Refractory of Kiln and Coal Fly Ash by Various of Greenbody Presure] Ayu Septriana; Azhar Azhar; Widi Astuti
Metalurgi Vol 32, No 3 (2017): Metalurgi Vol. 32 No. 3 Desember 2017
Publisher : National Research and Innovation Agency (BRIN)

Refractory is one type of ceramic material which is thermostable (high temperature resistant) and has the ability to maintain a good physical and chemical condition at high temperature. Manufacture of refractory in this study using used kiln refractory from cement industry and 15% coal fly ash as additional. This research analyzed the effect of green body pressure produced by physical properties of refractory which made from mixture of used refractory and coal fly ash. Used refractory crushed into large aggregate size -40 +80 mesh and small aggregate size -80 mesh, while fly ash -100 mesh. Then, the two of material mixed. Raw material pressed by press hydrauliuc, with a cube-shaped mold in 5 x 5 x 5 cm size. The pressure of green body varied in 8, 9, 10, 12, and 13 tons. The product tested by archimedes methode to getting apparent porosity and bulk density, and guarded hot plate methode standard use ASTM (C 177-04) to getting the cold crushing strengh and thermal conductivity. Higher pressure molding green body product was obtained with higher compressive strength and bulk density, with lower value of the apparent thermal conductivity and porosity. The highest value for the compressive strength and bulk density was 4.48 MPa; 1.119 g / cm3; the lowest value of thermal conductivity and apparent porosity is 11.60 W / m.K; 22.034%. Those values obtained from green pressure body 13 tons.AbstrakRefraktori merupakan salah satu jenis bahan keramik yang tahan terhadap panas (temperatur tinggi) dan memiliki kemampuan untuk mempertahankan kondisinya baik secara fisik maupun kimia pada temperatur tinggi tersebut. Pembuatan refraktori pada penelitian ini menggunakan bahan baku refraktori bekas pakai kiln pabrik semen dengan tambahan fly ash batubara. Penelitian ini menganalisis pengaruh tekanan green body dari campuran refraktori bekas pakai dan fly ash batubara yang dihasilkan terhadap sifat fisik refraktori tersebut.Bahan baku refraktori bekas pakai dihaluskan dengan distribusi ukuran agregat besar -40+80 mesh dan ukuran agregat kecil -80 mesh, sedangkan fly ash batubara berukuran -100 mesh. Setelah itu kedua bahan dicampur. Pemadatanbahan baku dilakukan dengan menggunakan alat press hydraulic, dengan cetakan berbentuk kubus dengan ukuran 5x5x5 cm. Dilakukan variasi tekanan campuran green body sebesar 8 ton, 9 ton, 10 ton, 11 ton, 12 ton, dan 13 ton. Pengujian produk dilakukan dengan uji apparent porosity (porositas) dan bulk density (densitas) dengan metode archimedes, cold crushing strenght (kuat tekan), dan uji konduktivitas termal bahan dilakukan dengan metode guarded hot plate menggunakan standar ASTM (C 177-04). Pengaruh tekanan green body dari campuran fly ash batubara dan refraktori bekas pakai kiln terhadap sifat fisik refraktori adalah semakin tinggi tekanan pencetakan green body, maka semakin tinggi nilai kuat tekan dan bulk density nya, sedangkan nilai konduktivitas termal dan apparent porosity akan semakin rendah. Nilai tertinggi untuk kuat tekan dan bulk density adalah 4,48 Mpa; 1,119 gr/cm3; nilai terendah konduktivitas termal dan apparent porosity adalah 11,60 W/m.K; 22,034 %. Nilai-nilai tersebut didapatkan dari tekanan green body 13 ton.

Pengambilan Lantanum dan Nikel dari Katalis Bekas Menggunakan Asam Sitrat: Peninjauan Performa secara Kuantitatif Menggunakan Response Surface Method (Lantanum and Nickel Recovery from Spent Catalyst Using Citric Acid : Quantitative Performance......) Himawan Tri Bayu Murti Petrus; Ardyanto Wijaya; Yusuf Iskandar; Danu Bratakusuma; Hendrik Setiawan; Wiratni Wiratni; Widi Astuti
Metalurgi Vol 33, No 2 (2018): Metalurgi Vol. 33 No. 2 Agustus 2018
Publisher : National Research and Innovation Agency (BRIN)

Heavy metals and Rare earth elements (REEs) are nowadays being used widely in many industries from electronics to petroleum industries as catalysts. However, their disposal caused serious problems to the environment. With the sharp growth in its usage, there is a better way to use and utilize valuable metals from secondary sources such as their disposal rather than using new raw materials. The aim of this work is to study the potential of citric acid as a leaching agent to extract lanthanum and nickel in various acid concentration and leaching temperature. The raw material used in this work is spent catalyst from Pertamina Refinery Unit VI, Balongan, Indonesia. The spent catalyst is decarbonized with a heat treatment at 725°C for 10 minutes before the leaching process. The leaching process used 0.1; 1; and 2 M of citric acid with a varied temperature of 30, 60, and 80°C. The lanthanum recovery was calculated by comparing the mass percentage of lanthanum before leaching process and after leaching process using Energy Dispersive X-Ray Spectroscopy (EDX). The results were analyzed by response surface methodology (RSM) and are proved to be a reliable method to depict and analyze the leaching characteristics. The molarity of the citric acid is the most significant independent variables used in the research for lanthanum recovery response. However, based on the Pareto analysis result there are no significant variables that affect the recovery of nickel. The second order polynomial fitting model is also proved to be compatible with the response of lanthanum recovery but is less compatible with nickel recovery. AbstrakPengambilan logam tanah jarang dan logam berat dari sumber sekunder (katalis bekas, limbah padat industri, dan abu terbang) menjadi alternatif karena pertimbangan lingkungan dan ketersediaan bijih di alam yang semakin sedikit. Pertimbangan tersebut yang mendasari studi tentang pengambilan lantanum dan nikel dari katalis bekas dengan menggunakan asam asetat. Bahan untuk penelitian ini adalah katalis bekas dari Penyulingan Pertamina Unit VI, Balongan. Sebelum pelindian dilakukan, katalis bekas didekarbonasi dengan perlakuan panas pada 725 °C selama 10 menit. Proses pelindian dilakukan dengan memvariasikan suhu dan konsentrasi asam asetat. Hasil eksperimen ditinjau menggunakanRSM (response surface methodology) dan terbukti sebagai metode yang dapat diandalkan untuk menggambarkan dan menganalisis karakter proses pelindian. Molaritas asam merupakan variabel independen yang secara signifikan mempengaruhi respon dalam pengambilan lantanum. Walaupun begitu, berdasarkan hasil analisis Pareto, tidak ada variabel yang secara signifikan mempengaruhi pengambilan nikel. Model fitting polinomial orde dua juga terbukti cocok dengan respon proses pengambilan lantanum daripada nikel. Hasil RSM menunjukkan bahwa kondisi optimum dari ekstraksilantanum dan nikel adalah pada pH 2 dan suhu 45 оC dimana lantanum dapat 100% terambil dan nikel sebanyak 60%.

Co-Authors Achmad Sofi Adil Jamali Adiwijaya Agus Hidayatullah Agustien Zulaidah Agustin, Niyar Candra Alvianda Ricky Lukman anggi solihah Anief Rufiyanto Aprimal Aprimal Apriyanti, Eny Ardyanto Wijaya Ayu Septriana Azhar Azhar Baswindro Baswindro Danu Bratakusuma Dinda Tri Novira Edy Sanwani Eko Wahyuni Fajar Nurjaman Fika Rofiek Mufakhir Ghina Khoerunnisa Halimatul Husni Hendrik Setiawan Himawan Tri Bayu Murti Petrus Imam Prasetyo January Jefry Prasetya Jondri Jondri Kasman Kasman Laksono Trisnantoro Lukman Nulhakim Luluk Siti Zulaechah Monna Rozana Muhammad Amin Nuslia Bayangkara Lamandhi Rini Julistia Riska Chairunisa Siska Siska SITI KHODIJAH CHAERUN Stefanus Lian Kristian Sukaryo Sukaryo Wiratni Wiratni Yustika Kusumawardani Yustika Kusumawardani Yustika Kusumawardani

Title

Found 23 Documents
Search

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Title Search

Found 23 Documents Search

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Title

Found 23 Documents
Search