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All Journal JURNAL KIMIA SAINS DAN APLIKASI POSITRON Jurnal Fisika Unand SEMIRATA 2015 JFA (Jurnal Fisika dan Aplikasinya) JURNAL KESEHATAN LINGKUNGAN: Jurnal dan Aplikasi Teknik Kesehatan Lingkungan INDONESIAN JOURNAL OF APPLIED PHYSICS JI-KES (Jurnal Ilmu Kesehatan) Jurnal Kelautan Nasional Jurnal Hilirisasi IPTEKS (JHI) Jurnal Ilmu Fisika INTEGRITAS : Jurnal Pengabdian BERNAS: Jurnal Pengabdian Kepada Masyarakat Natural Science: Jurnal Penelitian Bidang IPA dan Pendidikan IPA Jurnal Pengabdian kepada Masyarakat Nusantara International Journal Of Science, Technology & Management (IJSTM) Makara Journal of Science Indonesian Journal of Community Empowerment and Service
Astuti Astuti
Departement Fisika, Fakultas Matematika Dan Ilmu Pengetahuan Alam, Universitas Andalas
Religion Aerospace Engineering Agriculture, Biological Sciences & Forestry Humanities Astronomy Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Dentistry Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Health Professions Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Mathematics Mechanical Engineering Neuroscience Nursing Physics Public Health Social Sciences Transportation Veterinary Other

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Audit Delay : Influencing Factors (Case Study Of Large Trading Companies On The Indonesia Stock Exchange For The Period 2017 – 2021) Astuti, Astuti; Dewi Nainggolan, Christine; Dermawan Sembiring, Lenny
International Journal of Science, Technology & Management Vol. 4 No. 5 (2023): September 2023
Publisher : Publisher Cv. Inara

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46729/ijstm.v3i6.683

Abstract

The timeliness of the delivery of financial statements is an important factor in presenting relevant information. Obstacles in the accuracy of the submission of financial statements can certainly affect the market's response to the financial statements presented. This study aims to analyze the factors that affect audit delay, including company size, leverage and profitability. The implementation of the study was carried out on thirteen Large Trading Companies during the 2017-2021 period which totaled 65 data. The data analysis techniques used in this study are descriptive statistical analysis, classical assumption testing, multiple linear regression analysis, and hypothesis testing. The results showed that partially the company size has a significant effect on audit delay, leverage has a significant effect on audit delay, while profitability has no significant effect on audit delay.
Pengaruh Waktu Hidrotermal Terhadap Sifat Optik Nanokomposit Fe3O4@CQD (Carbon Quantum Dots) Putri Azima Rafsanjani; Astuti Astuti
Jurnal Fisika Unand Vol 14 No 6 (2025)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.14.6.561-568.2025

Abstract

This study aims to synthesize Fe₃O₄@CQD nanocomposites using a hydrothermal method with time variations to study their effects on the structural and optical properties of the material. Fe₃O₄ nanoparticles were obtained through a coprecipitation method, while CQDs were synthesized from the extract of sappan wood (Caesalpinia sappan L.) which is natural, environmentally friendly, and has the potential as a fluorescent material. The results of XRD characterization showed that Fe₃O₄ has a crystal size of 22.476 nm, while the addition of CQDs increased the crystal size of the nanocomposite. FTIR analysis confirmed the presence of typical functional groups such as Fe–O, O–H, C–H, and C=O indicating the presence of CQDs in Fe₃O₄. UV-Vis test shows that Fe₃O₄@CQD has an absorption peak in the wavelength range of 300-700 nm, while the fluorescence test shows that the emission intensity increaseswith increasing hydrothermal time, with the emission peak at a wavelength of 600–650 nm.
Sintesis dan Karakterisasi Struktur dan Sifat Fluresensi Nanokomposit Fe3O4/CQD@ZIF-8 Chika Yandora; Astuti Astuti; Dwi Puryanti
Jurnal Fisika Unand Vol 15 No 3 (2026)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.15.3.323-330.2026

Abstract

Advances in nanotechnology are driving the development of multifunctional materials, one of which is magnetic-luminescent nanocomposites that combine magnetic and fluorescent properties in a single system. These materials hold great potential for biomedical applications, particularly in bioimaging. Fe₃O₄ nanoparticles are widely used as magnetic materials due to their biocompatibility and low toxicity, while Carbon Quantum Dots (CQDs) are used as luminescent materials because they exhibit strong fluorescence, high photostability, and are non-toxic. However, Fe3O4/CQD nanocomposites suffer from particle agglomeration and quenching effects. To address these issues, encapsulation was performed using Zeolitic Imidazolate Framework-8 (ZIF-8), which possesses biocompatible, biodegradable properties, and high surface area and porosity. In this study, Fe₃O₄/CQD@ZIF-8 nanocomposites were synthesized. Coating with ZIF-8 is expected to act as a protective layer that has the potential to reduce agglomeration and minimize the quenching effect. The crystalline structure and functional groups of the material were characterized using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR), while its optical properties were analyzed using fluorescence spectroscopy.
Sintesis dan Karakterisasi Struktur dan Sifat Magnet Nanokomposit Fe3O4@PEG:ZnO Astuti Astuti; ihda khaira; syukri Arief; Sri Rahayu Alfitri Usna
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 12, No 2 (2022): October
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v12i2.58514

Abstract

Fe3O4@PEG:ZnO nanocomposites were synthesized by the coprecipitation method with various of the samples were Fe3O4, Fe3O4@ZnO (1:1), Fe3O4@PEG: ZnO (1:2), and Fe3O4@ PEG: ZnO (1:3). The samples were synthesized with variation in the concentration of ZnO to Fe3O4. The concentration ratio of (Fe3O4:ZnO) were (1:1), (1:2), and (1:3). In addition, polyethylene glycol (PEG) is also used to prevent the agglomeration of Fe3O4. Sample characterization was carried out using X-Ray Diffraction (XRD), Transmission Electron Microscope (TEM), Fourier Transform Infrared (FTIR), Particle Size Analyzer (PSA), and vibrating Sample Magnetometer (VSM). The XRD patterns show that the sample is composed of Fe3O4phase and ZnO phase with crystal structure cubic and wurtzite respectively. The TEM image shows the formation of a core-shell structure where PEG: ZnO is the shell and Fe3O4 is the core. From the FTIR results, there are C-O and C-C bonds which indicate the formation of PEG, Fe-O bonds indicate the formation of Fe3O4 and Zn-O bonds indicate the formation of ZnO. Characterization with PSA obtained particle sizes of 33 nm, 23 nm, and 16 nm with particle size distributions of 25%, 50%, and 75% so that the average particle size is 24 nm. The VSM results show that Fe3O4@PEG: ZnO (1:2) nanocomposite has a high magnetic saturation of 66.58 emu/g, with superparamagnetic properties, which has the potential to be developed as a bioimaging material.
Sintesis Karbon Aktif dari Kulit Pisang untuk Pemurnian Air Tambang Emas di Sungai Batang Palangki Kabupaten Sijunjung dari Logam Berat: Rahmah Khairati Maiza, Melanz Hasan, Muhammad Fadly, Astuti Rahmah Khairati Maiza Rahmah Khairati Maiza; Melanz Hasan Melanz Hasan; Astuti Astuti
Jurnal Fisika dan Aplikasinya Vol 15 No 1 (2019): January 2019 Edition
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v15i1.3815

Abstract

The purification of wastewater from the gold mine from heavy metals in Batang Palangki, Sijunjung Regency has been carried out. Prior to the purification of this wastewater, water samples were first measured by heavy metal content using Inductively Coupled Plasma (ICP) and found 24 heavy metal elements of which 8 of them were above the standard threshold of water quality standards. Purification of water using adsorption technique with adsorbent activated carbon from banana kepok skin. This study used activated carbon with concentration concentration of 20%, 25%, 30%, and 35% H2SO4 activator. Activated carbons were added to the measuring cup containing 100 ml of gold mine wastewater, stirred to homogeneous and allowed to settle to the bottom of the measuring cup, then filtered water using filter paper, measured pH, heavy metal content and electrical conductivity values. Based on the research results, activated carbon with the most optimal absorption is at a concentration of 35% with the average pore size of activated carbon of 24.6 m. This data was obtained from the Inductively Coupled Plasma (ICP) tool by comparing the heavy metal content of wastewater before and after the activated carbon treatment. The purified water is in accordance with Minister of Health Regulation no. 416 / MENKES / PER / IX / 1990 on water quality requirements and Government Regulation no. 82 of 2001 on the Management of Water Quality and Control of Water Pollution.
Co-Authors Abdurrahim, Muhammad Rhohid Adrial, Rico Afdal Afdal Afdhal Muttaqin Aflahannisa Aflahannisa Aflahannisa, Aflahannisa Ahmad Fauzi Pohan Alief, Iqbal Alimin Mahyudin Alvionita, Novia Amri Bakhtiar Anggun Pradilla Sandi Anggun Pradilla Sandi, Anggun Pradilla Apriyanto, Apriyanto Aprizon Putra Arasi Syamsir Arasi Syamsir Ardian Putra Arif Budiman Arsita, Yuliani Ayu Mairoza Ayu Mairoza Baqi, Ahmad Iqbal Betti Delmifiana Betti Delmifiana Bunga Novia Chika Yandora Citra Mardatillah Taufik Citra Mardatillah Taufik Claudia, Geby Dahyunir Dahlan Damanhuri, Harfiandri Damayanti, Elok Dedi Hermon Dedi Mardiansyah Defri Rahman Delni Sriwita Delni Sriwita Depi Nurdiati Depi Nurdiati, Depi Devi Pebrina Devi Pebrina Dewi Nainggolan, Christine Dian Fitriyani Dian Milvita Dwi Pujiastuti Dwi Puryanti Efendi, Zudit Elistia Liza Namigo, Elistia Elvaswer Elvaswer Erika Linda Yani Nasution F, Maduri Fauzi, Abas Feriska Handayani Irka, Feriska Handayani Firmansyah - Firmansyah - Fitiria, Zakiatul Giyalovta, Algozan Degesha Hamzan Wadi Hari Gusti Firnando Hari Gusti Firnando, Hari Gusti Harmadi Harmadi Harmen Zanur Harun, Lalu Ahmad Hawariyi Ola Yuzria Hawariyi Ola Yuzria Haya, Nabila Fadia Helga Dwi Fahyuan Helga Dwi Fahyuan Hendro Susilo Hidayati Susana Hidayati Susana, Hidayati Homiswadi, Homiswadi Hudoyo, Sapto Husnah, Ilma ihda khaira Ihda Khaira Ilma Husnah Imam Taufik Imam Taufiq Indang Dewata Indriwati Indriwati Iqbal Alief Ira Olimpiani Ira Olimpiani, Ira Jaslia, Nora Zenestry Juwita Safitri, Juwita Kasman Ediputra, Kasman Khaira, Ihda Kurniaan, Rengga Adit Kurniawan, Rengga Adit Laila Sari Laila Sari Lailatul Marhamah Lenny Dermawan Sembiring Lestari, Asril Ayu Lidya Mozanna Machmudah, Machmudah Maduri F Mahdi Mahdi Mahdi Mahdi Mahdi Mahdi, Mahdi Mairoza, Ayu Mairoza, Ayu Maiza, Rahmah Khairati Mardiyanto - Mardiyanto - Marhamah, Lailatul Marzuki Marzuki Mayestika, Nadya Melanz Hasan Melanz Hasan Melda Taspika Melda Taspika, Melda Meqorry Yusfi Mieke Wulandari Mirahwati, Mirahwati Mohammad Ali Shafii Mora Mora Mora Mozanna, Lidya Muhammad Ilham Muhammad Ilham Muhammad Rhohid Abdurrahim Muhibbatun, Muhibbatun Muldarisnur, Mulda Mutya Vonnisa Nabila Fadia Haya Nadya Mayestika Negara, Vamellia Sari Indah Nila Sriwahyuni Nila Sriwahyuni, Nila Ningsi, Sulastriya Nini Firmawati Noni Nopriantina Noni Nopriantina Nora Zenestry Jaslia Noraida Novia Alvionita Novia, Bunga Novita, Deli Nurhaleni, Nurhaleni Nurhidayah Sari, Nurhidayah NURUL AZIZAH Okti Mulyani, Okti Pebrina, Devi Peni Alpionita Peni Alpionita, Peni Putri Azima Rafsanjani Putri Pratiwi Radika, Rezi Rahma Hayati Rahma Hayati Rahma Nella Rahma Nella Rahmad Rasyid Rahmah Khairati Maiza Rahmah Khairati Maiza Rahmah Khairati Maiza Rahmat Rasyid Rahmawati, Sri Andlina Ramacos Fardela Ramadhani, Melvira Raudhoh Raudhoh Rengga Adit Kurniaan Rengga Adit Kurniawan Resti Rahayu Resti Rahayu Rhomar, Zeflianto Riana Riana, Riana Risda Tussa’adah Rizchi Aulia Utami Rozi, Tika Yulian Rudi Febriamansyah Santika, Rahma Semeidi Husrin Setiani, Dwi Aluh Sintha Widiawati Sonya Rahayu Sonya Rahayu Sri Handani Sri Oktamuliani Suci Miza Marta Ulfia Suci Miza Marta Ulfia, Suci Miza Marta Suparno . Susilo, Hendro Syukri Arief Tika Yulian Rozi Trengginas Eka Putra Sutantyo Try Al Tanto Tussa’adah, Risda Usna, Sri Rahayu Alfitri Utami, Rizchi Aulia Vamellia Sari Indah Negara Veronica, Yessi Virrisya Virrisya Virrisya, Virrisya Widiawati, Sintha Wildian Wildian Wilson Novarino Winata, Rizki Hardian Winda Rahayu Okta Yanti Winda Rahayu Okta Yanti Wulandari, Mieke Yanti, Winda Rahayu Okta Yanti, Winda Rahayu Okta Yessi Veronica Yolanda Oktaviani Yolanda Oktaviani Yossi Rahmadeni Yuliani Arsita Yulistriani, Yulistriani yunasfi yunasfi Yusfi, Meqqory Zanur, Harmen Zaunit, Muthia Miranda Zeflianto Rhomar Zelin, Hikmatul Gusti Fadhia Zudit Efendi Zudit Efendi Zulfi Zulfi Zulfi, Zulfi Zulhendri Zulhendri