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All Journal Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Jurnal Sains Materi Indonesia Indonesian Journal of Electrical Engineering and Informatics (IJEEI) Journal of Engineering and Technological Sciences JFA (Jurnal Fisika dan Aplikasinya) POLYGLOT Diligentia: Journal of Theology and Christian Education Prosiding Konferensi Nasional PKM-CSR PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL)
Sitompul, Henni
Universitas Pelita Harapan
Religion Humanities Astronomy Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Materials Science & Nanotechnology Nursing Physics Public Health Social Sciences Other

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Synthesis and Characterization of Ba0.6Sr0.4Fe12O19/LaMnO3 Composites as Microwave Absorbers Yohanes Edi Gunanto; Maya Puspitasari Izaak; Henni Sitompul; Wisnu Ari Adi
Indonesian Journal of Electrical Engineering and Informatics (IJEEI) Vol 9, No 4: December 2021
Publisher : IAES Indonesian Section

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52549/ijeei.v9i4.3239

Abstract

The synthesis and characterization of Ba0.6Sr0.4Fe12O19/LaMnO3 composite material has been successfully carried out by mechanical alloying method using high energy milling. Crystal structure and surface morphology were characterized using x-ray diffraction and scanning electron microscopy. While the value of magnetization and the ability to absorb microwaves, vibrating sample magnetization and vector network analyzing were used, respectively. With variations in weight, does not change the crystal structure. The Ba0.6Sr0.4Fe12O19phase has a hexagonal structure and the LaMnO3 phase has an orthorhombic structure. Surface morphology has a heterogeneous size in the range of 200-450 nm with the form of platelets. The composite material Ba0.6Sr0.4Fe12O19/LaMnO3 is a hard-soft magnetic material with a magnetic saturation of Ms ~ 46.83 emu/g, Mr ~ 28.8 emu/g, and a coercive field of Hc ~ 3.88 kOe. The minimum reflection loss value is – 13.0 dB at 11.2 GHz frequency and 1.52 GHz bandwidth.
THE STRUCTURAL, IMPEDANCE AND DIELECTRIC A FERRITE CORE OF IRON MANGANITE AND ITS COMPOSITE Yohanes Edi Gunanto; Henni Sitompul; Maya Puspitasari Izaak; Wisnu Ari Adi
Jurnal Sains Materi Indonesia Vol 23, No 1: OCTOBER 2021
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/jsmi.2021.23.1.6303

Abstract

THE STRUCTURAL, IMPEDANCE AND DIELECTRIC A FERRITE CORE OF IRON MANGANITE AND ITS COMPOSITE. Samples with single-phase MnFeO3 and multiphase MnFeO3/ZnFe2O4 (30/70), and MnFeO3/ZnFe2O4/LaMnO3 (30/40/30) have been successfully prepared as ferrite cores by the solid-state reaction method using high energy milling. Crystal structure, surface morphology, impedance, AC-conductivity and dielectric quantities, such as dielectric constant and dielectric loss have been studied. The crystalline structures for MnFeO3, ZnFe2O4, and LaMnO3 are hexagonal, cubic and monoclinic, The Rietveld program used for XRD analysis resulted in the composition fractions of single phase MnFeO3, multiphase MnFeO3/ZnFe2O4 (31/69), and MnFeO3/ZnFe2O4/LaMnO3 (31/40/29). The morphology of all samples has a heterogeneous shape and size with low porosity. The single-phase impedance of MnFeO3 is higher than the multiphase sample. The conductivity of the three samples has the same pattern, which is relatively constant at low frequencies and begins to increase at frequencies above 10 kHz. The dielectric constant and dielectric loss (tan ????) have high values at low frequencies, decrease exponentially with increasing frequency and are relatively fixed at high frequencies.
Microwave Absorbing Material of Ba0.95La0.05Fe12-2xZnxTixO19 (x = 0; 0.5; and 1.0) with Broadband Characteristic at X-band Frequency Yohanes Edi Gunanto; Henni Sitompul; Maya Puspitasari Izaak; Yosep Sarwanto; Wisnu Ari Adi
Journal of Engineering and Technological Sciences Vol. 54 No. 2 (2022)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2022.54.2.2

Abstract

In this study, hexaferrite Ba0.95La0.05Fe12-2xZnxTixO19 (x = 0; 0.5; and 1.0) was synthesized and characterized, which can be applied as microwave absorber in the X-band frequency range. It is a potential candidate for a radar absorbing material for microwave absorption, particularly for use in anti-radar paint in the defense sector. Samples were prepared using solid state reaction synthesis with high energy milling. After sintering at the right temperature, the samples were characterized using an X-ray diffractometer (XRD), a scanning electron microscope (SEM), a vibrating-sample magnetometer (VSM) and vector network analysis (VNA). The XRD characterization results indicated that all samples were in phase and had a hexagonal lattice structure with a P63/mmc space group and a crystallite size between 38 and 45 nm. The surface morphology of the characterization results using SEM showed a heterogeneous particle shape with particle sizes ranging from 140 to 200 nm. Substitution of Ti4+ ions for Fe3+ ions by Zn2+ ions resulted in a decrease of the magnetic saturation (Ms), the magnetic remanence, and the sample’s coercivity field. With a sample thickness of 1.5 mm, the VNA results confirmed that the ability to absorb microwaves and bandwidth will increase along with increase of the substitution value x. The reflection loss value was about -13.3 dB at a frequency of around 11 GHz, with a bandwidth of 1.4 GHz for the sample with x = 1.0 composition.
Synthesis and Corrosion Test of Magnesium Zinc-5% Hydroxyapatite (MgZn-5% wt.Hap) Biocomposites as a Bone Biodegradable Implant Material Henni Sitompul; Kiagus Dahlan; Deni Noviana; Marzuki Silalahi; Sulistioso Giat Sukaryo; Yohanes Edi Gunanto
Jurnal Fisika dan Aplikasinya Vol 15, No 1 (2019)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (904.498 KB) | DOI: 10.12962/j24604682.v15i1.3797

Abstract

In recent years, development of magnesium (Mg) as biodegradable implant very rapidly in orthopedic applications. This is due to its young’s modulus close to young modulus of natural bone. However, Mg implants demonstrate higher biological activity which could cause high degradation rate in human bio-environment. Consequently, needed to develop Mg-based alloys with superior corrosion performance. In the present study, it has been attempted to develop biocomposite of Magnesium Zinc-5% Hydroxyapatite (MgZn-5%HAp) as biodegradable bone implant. The biocomposites were prepared by adding 5wt.% powders to MgZn powder and then were sintered at temperature 350 oC in vacuum furnace for holding an hour. The characterization of MgZn-5wt%HAp biocomposite was examined by Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) and X-ray diffraction (XRD) while corrosion tested by potensiostat. The SEM / EDS and XRD results indicated that some of the Zn atoms have dissolved in Mg to form a MgZn solid solution. The SEM results also showed that the MgZn-5%HAp biocomposite has a microstructure with a matrix Mg and HAp at the grain boundary. The presence of HAp in the sample resulted in a smaller crystallite size and corrosion rate compared to  the one with MgZn alloy.
Development of magnetic functional materials based on carbon/manganite/ferrite composites for Microwave absorber materials applications Maya Puspitasari Izaak; Yohanes Edi Gunanto; Henni Sitompul; Wisnu Ari Adi
Jurnal Fisika dan Aplikasinya Vol 17, No 2 (2021)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v17i2.8978

Abstract

The synthesis of carbon/manganite/ferrite composite materials for microwave absorber applications has been successfully carried out with variations in the composition of 15:55:30 and 15:45:40 (wt%). This composition was successfully confirmed based on the analysis of the X-ray diffraction pattern using the GSAS program. The refinement results show that each phase of each composite has a good structure. Based on surface morphological observations, it is known that the composite samples have varying particle sizes of around 150-500 nm which are evenly distributed over the entire surface of the sample. The result of the microwave absorption analysis implies that the difference in composition results in a slight increase of the reflection loss and the presence of a new absorption peak at a frequency of 4.36 GHz. Our result underlines that the characteristic of microwave absorption in composites is insignificantly influenced by the composition of the material as the absorption properties are mainly affected by the respective phases that form it, not by the entire phase of the composite.
The synthesis of TiO2 nanoparticles by Milling and Coprecipitation Mixed Method Maya Puspitasari Izaak; Yohanes Edi Gunanto; Henni Sitompul; Wisnu Ari Adi
Jurnal Fisika dan Aplikasinya Vol 16, No 2 (2020)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v16i2.5199

Abstract

Ilmenite type Fe2O3 waste (which is processed from natural iron sand) was processed into TiO2 nanoparticles powder carried out by leaching with HCl and then using high-energy milling (HEM) for 50 hours. The characteristics of the powder such as particle size, size distribution and phases were analyzed using various techniques such as XRD, SEM, EDS and particle size analyzer. Synthesis and characterization of ilmenite type iron sand have been successfully made into TiO2 by milling and coprecipitation mixed method. The purity level of TiO2 was obtained by 85.01%. Particle size of TiO2 was approximately 500 nm.
Effect of HAp on Characterization of MgZn-xHAp Biocomposites Henni Sitompul; Yohanes Edi Gunanto; Maya Puspitasari Izaak
Jurnal Fisika dan Aplikasinya Vol 17, No 1 (2021)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v17i1.7411

Abstract

Research on Mg as biodegradable materials in orthopedics has been carry out intensively in the 17 years. Various studies conducted to produce material that is superior in mechanical properties and corrosion resistance. One of the developments carry out is to make Mg-based composite. This study aims to see the effect of HAp on Mg6ZnHAp composites. The biocomposites were synthesized by mixing the HAp powder on the Mg6Zn powder mixture with the composition of 5%, 7% and 9% using ball milling for 30 minutes. The material is sintered at 350 oC and held for one hour. Biocomposites were characterized by SEM/EDS, X-ray diffraction (XRD) and Potentiostat. The SEM/EDS results showed that the larger the HAp composition resulted in the smaller grain size. The crystallite size of the material decreases with increasing HAp composition in the material. The presence of HAp in the material also affects the corrosion rate. The greater HAp composition in the material will result in better corrosion resistance. 
PENTINGNYA KOMPETENSI PROFESIONAL BAGI MAHASISWA CALON GURU KRISTEN DALAM KEGIATAN PEMBELAJARAN MATEMATIKA [THE IMPORTANCE OF PROFESSIONAL COMPETENCE FOR PRE-SERVICE CHRISTIAN TEACHERS IN MATHEMATICS LEARNING ACTIVITIES] Ester Putri Febriana; Tanti Listiani; Henni Sitompul
Polyglot Vol 17, No 1 (2021): JANUARY
Publisher : Universitas Pelita Harapan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19166/pji.v17i1.2442

Abstract

Schools are educational institutions that are primarily focused on achieving educational goals. In achieving these goals, schools need competent teachers. Competent teachers are teachers who have four teacher competencies, namely learning management (pedagogical competence), potential development (social competence), academic mastery (professional competence), and personality attitudes (personality competence). A teacher must possess these four teacher competencies in order to support his/her role as an educator. Based on the field experience program conducted by pre-service teachers, it is evident that pre-service teachers lack professional competence. The purpose of writing this paper is to further examine the importance of professional competence for pre-service teachers in supporting the ongoing learning activities at a school, especially for a Christian teacher. The importance of professional competence for a pre-service teacher can provide confidence when teaching, the capacity to guide in mathematics learning activities, and the ability to carry out his/her role as a restoration agent. To improve professional competence, teachers should conduct microteaching activities, study, and attend seminars and other benefical activities.BAHASA INDONESIA ABSTRACT: Sekolah merupakan lembaga pendidikan yang paling utama berfokus kepada pencapaian tujuan-tujuan pendidikan. Dalam mencapai tujuan pendidikan yang telah ditetapkan, sekolah membutuhkan seorang guru yang berkompeten. Guru yang berkompeten adalah guru yang memiliki empat kompetensi guru yaitu pengelolaan pembelajaran (kompetensi pedagogi), pengembangan potensi (kompetensi sosial), penguasaan akademik (kompetensi profesional), dan sikap kepribadian (kompetensi kepribadian). Keempat kompetensi guru tersebut haruslah dimiliki oleh seorang guru agar dapat mendukung perannya sebagai seorang pendidik. Berdasarkan program pengalaman lapangan yang telah dilakukan oleh mahasiswa calon guru, dapat dilihat bahwa mahasiswa calon guru masih kurang dalam kompetensi profesional. Tujuan penulisan paper ini untuk mengkaji tentang pentingnya kompetensi profesional bagi seorang mahasiswa calon guru dalam mendukung kegiatan pembelajaran yang sedang berlangsung di sekolah, terutama dalam diri seorang guru Kristen. Pentingnya kompetensi profesional bagi seorang mahasiswa calon guru, yaitu memberikan rasa percaya diri ketika mengajar, guru dapat menjadi penuntun dalam kegiatan pembelajaran matematika, serta guru dapat menjalankan perannya sebagai agen restorasi. Dalam meningkatkan kompetensi profesional, guru disarankan untuk dapat melakukan kegiatan microteaching, belajar, mengikuti seminar dan kegiatan-kegiatan yang dapat meningkatkan kompetensi tersebut.
KARAKTERISASI DAN ANALISIS UKURAN KRISTALIT PADA PROSES PEMADUAN Mg-Zn DENGAN METODE ULTRASONIK Henni Sitompul; Kiagus Dahlan; Deni Noviana; Sulistioso Sulistioso; Marzuki Silalahi
PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL) Vol 5 (2016): PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL) SNF2016
Publisher : Program Studi Pendidikan Fisika dan Program Studi Fisika Universitas Negeri Jakarta, LPPM Universitas Negeri Jakarta, HFI Jakarta, HFI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (794.1 KB) | DOI: 10.21009/0305020214

Abstract

Magnesium is a metal that is being developed in the field of biomaterials, especially as biodegradable implants. MgZn alloy has mechanical properties and corrosion resistance that are better than other Mg binary alloys. The process of conducting the MgZn integration in this study, used the ultrasonic waves that flows in toluene as a medium. Ultrasonic waves will generate the cavitation to the medium, and the explosion of the cavitation will produce a high temperature and pressure in order to combine Mg with Zn. The characteristic of using XRD showed that the ultrasonic treatment for 50 hours can increase the crystallites size of Mg and Zn. However, it is not yet able to produce the MgZn alloy. This is affected by the presence of the Mg(OH)2’s layer on the Mg particles. SEM/EDS result showed that 50 hour ultrasonic treatment can clean the Mg from the layer of Mg(OH)2. Keywords: Ultrasonic, Cavitasi, MgZn, Biodegradable.
DAMPAK BIMBINGAN BELAJAR DELTA HKBP GADING SERPONG PADA MASA PANDEMI COVID-19 Henni Sitompul; Yohanes Edi Gunanto; Maya Puspitasari Izaak; Lia Kristina Sianipar; Kurniawati Martha
Prosiding Konferensi Nasional Pengabdian Kepada Masyarakat dan Corporate Social Responsibility (PKM-CSR) Vol 5 (2022): PERAN PERGURUAN TINGGI DAN DUNIA USAHA DALAM AKSELERASI PEMULIHAN DAMPAK PANDEMI
Publisher : Asosiasi Sinergi Pengabdi dan Pemberdaya Indonesia (ASPPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37695/pkmcsr.v5i0.1555

Abstract

Kondisi Pandemi telah mengubah sistem pembelajran di Indonesia, pemberlakuan belajar dari rumah membuat budaya belajar yang baru bagi siswa dan juga menambah peran bagi orang tua. Orang tua diharuskan mendampingi anak-anak mereka belajar dari rumah. Namun tidak semua orang tua dapat mendampingi anak-anak mereka mempelajari materi di sekolah. Oleh karena itu dibutuhkan bantuan dari luar untuk mendukung pertumbuhan belajar anak mereka. Bimbingan belajar Delta merupakan salah satu solusi atas permasalahan ini. Bimbingan belajar Delta HKBP Gading serpong merupakan kegiatan pengabdian kepada masyarakat yang dilakukan oleh program studi Pendidikan Fisika Universitas Pelita Harapan dengan bermitra dengan seksi Pendidikan HKBP Gading serpong. Selama masa pandemi, kegiatan ini dilakukan secara online demi menghindari penyebaran virus corona yang sedang merebak. Proses belajar mengajar dilakukan melalui aplikasi Whatsapp, Zoom, atau google classroom, tergantung kondisi jaringan dan perangkat yang dimiliki oleh tutor dan siswa. Pembelajaran dilakukan setiap hari sabtu dengan durasi 90 menit. Pada akhir tahun ajaran 2021/2022 dilakukan survey kepada siswa, orang tua dan tutor untuk melihat hasil dari kegiatan ini. Dari hasil survey diketahui bahwa bimbingan belajar Delta dapat membantu siswa untuk memahami materi mata pelajaran yang sulit bagi mereka. Hal ini dibuktikan dengan sebagian besar siswa yang mendapatkan nilai dengan kategori baik dan baik sekali untuk mata pelajaran IPA, Bahasa inggris dan Matematika. Mahasiswa yang menjadi tutor juga merasa bahwa kegiatan ini mendukung pembentukan profil lulusan dalam diri mereka.
Co-Authors Deni Noviana Emiliana Emalallan Ester Putri Febriana Fetty Hosanna Sigalingging Kiagus Dahlan Kiagus Dahlan Kurniawati Martha Kurniawati Martha Lia Kristina Sianipar Lia Sianipar Marzuki Silalahi Marzuki Silalahi Maya P Izaak Purwamargapratala, Yustinus Sulistioso Giat Sukaryo Sulistioso Sulistioso Tamba, Kimura Patar Tanti Listiani Wisnu Ari Adi Wisnu Ari Adi Wisnu Ari Adi Wisnu Ari Adi Wisnu Ari Adi Yohanes E Gunanto Yohanes Edi Gunanto Yosep Sarwanto Yustinus Purwamargapratala