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All Journal Pendidikan Geografi Jurnal Vokasi Sinergi Polmed : Jurnal Ilmiah Teknik Mesin INTERNATIONAL JOURNAL OF MECHANICAL COMPUTATIONAL AND MANUFACTURING RESEARCH Jurnal Polimesin
Erna Juwita
Unknown Affiliation
Automotive Engineering Civil Engineering, Building, Construction & Architecture Control & Systems Engineering Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Social Sciences

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STUDI LOKASI PUSAT PEMERINTAHAN KABUPATEN DHARMASRAYA Sari, Zesa Mulyanda; Juwita, Erna; Zuriyani, Elvi
Pendidikan Geografi Vol 2, No 2 (2013): Jurnal Wisuda Ke 47, Pendidikan Geografi
Publisher : STKIP PGRI Sumbar

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

Abstract

Problems in this area is the complaints and the perception of the public about the central government and local services are too far away from where people live well to take care of the administrative requirements such as taking care of Birth Certificate, Family Card (KK), and other purposes, the central government since the distance is too far .This research study aims to determine the location of County Government Center Dharmasraya, this research is descriptive. Population in this research is the head of a family that is in Nagari Koto Baru, Dharmasraya, totaling 3,327 households (samples taken with proportional random sampling technique to the proportion of 5% so that the sample amounted to 164 households.The research found that: 1) Distance Nagari Koto Baru with the central government in Dharmasraya about 35 km. Based on the average rating of the 164 respondents, looks very much about (87.5%), travel time (70%) responded ± 2 hours more / longer, while the costs (55%) say the economic impact on society of the cost of the society should be removed. 2) Infrastructure facilities and infrastructure Nagari Koto Baru with the central government in Dharmasraya average score was 2.94 with a performance level of 74.6% of respondents who are in pretty good criteria. This shows that the infrastructure in Dharmasraya good views of the availability of facilities and infrastructure. 3) Impact of the district administrative center away from residential communities in Nagari Koto Baru is very influential on the distance, time and expenses to be incurred. Whereas in view of the infrastructure facilities and infrastructure in Nagari Koto Baru less influence on this area.
Sosialisasi Penggunaan Flash Card pada Mata Pelajaran Fisika dalam Upaya Meningkatkan Minat Belajar Siswa di SMAS Dr. Wahidin Sudirohusodo Medan Surbakti, Benar; Manurung, Agnes Br.; Andaresta, Windy; Juwita, Erna; Cuana, Rona
Jurnal Vokasi Vol 9, No 2 (2025): Juli
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/vokasi.v9i2.7231

Abstract

Kegiatan Pengabdian Kepada Masyarakat (PKM) yang dilakukan di SMA Swasta Dr. Wahidin Sudirohusodo merupakan salah satu upaya dalam peningkatan kualitas pendidikan sains, khususnya fisika. Pemilihan sekolah tersebut sebagai mitra didasarkan pada kenyataan bahwa masih digunakannya metode pembelajaran yang monoton, kurangnya kreativitas dalam membuat media pembelajaran yang menarik, dan banyak siswa yang mengalami kesulitan dalam memahami materi fisika. Tujuan kegiatan ini adalah untuk memberikan edukasi mengenai penggunaan media pembelajaran yang interaktif dan praktis sehingga dapat membantu meningkatkan pemahaman siswa terhadap pelajaran fisika. Sebagai bentuk upaya dalam mencapai tujuan tersebut, maka dilakukan sosialisasi mengenai penggunaan flash card dalam pembelajaran fisika, dengan peserta yang terdiri dari 6 orang guru dan 20 siswa SMA kelas XI. Flash card yang dibuat dalam kegitan ini merupakan media pembelajaran interaktif berbasis teknologi yang menyajikan video pembelajaran menarik dan praktis digunakan oleh siswa. Hasil dari kegiatan ini adalah tercipta antusias yang tinggi pada peserta dalam mengikuti kegiatan sosialisasi, terlihat respon positif dari mereka untuk mengetahui lebih dalam mengenai penggunaan flash card dalam pelajaran fisika. Kedepannya diharapkan kegiatan ini dapat meningkatkan minat dan motivasi siswa terhadap pelajaran fisika yang dianggap sulit dengan memanfaatkan perkembangan teknologi dan mendorong kreativitas guru dalam mengembangkan media pembelajaran yang sesuai dengan kebutuhan dan karakteristik siswa.
Dimensional measurement calibration of dial calipers based on JIS B 7507: 2016 standard in the measurement laboratory Manurung, Agnes Br; Purba, Adi Syahputra; Manalu, Ari Angga; Juwita, Erna; Aryswan, Adhe
International Journal of Mechanical Computational and Manufacturing Research Vol. 14 No. 1 (2025): May: Mechanical Computational And Manufacturing Research
Publisher : Trigin Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35335/computational.v14i1.265

Abstract

Dial calipers are very frequently used by both measurement laboratories and production. Dial calipers need to be calibrated every 12 months. The purpose of this study is to provide an understanding of how to calibrate a dial caliper, using a method based on JIS B 7507:2016 Standard. The JIS standard itself provides guidance and reference for dial caliper calibration. Based on the calibration results obtained, it is known that the dial caliper has deviation or error values in each measurement (outside, inside, depth, and step) with values of 0.0200 mm and -0.01000, referring to an accuracy of +/-0.03mm. After evaluation based on the standard, these error values still meet the requirements of JIS B 7507-2016. The benefit of this calibration is dial calipers are important to calibrate both before and after use to ensure optimal accuracy and consistent measurement results and also this calibration performed is sufficiently valid and reliable.
ANALISIS EFISIENSI BOILER MENGGUNAKAN BAHAN BAKAR BIOMASSA DI PLTU PT. GIP GROWTH ASIA Nainggolan, Rufinus; Ritonga, Fatima Sari; Juwita, Erna; Bangun, Ary Johanda; Marbun, Abri Andry Saresa
SINERGI POLMED: Jurnal Ilmiah Teknik Mesin Vol. 6 No. 2 (2025): Edisi Agustus
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/sinergipolmed.v6i2.2498

Abstract

Boiler atau ketel uap yang dimiliki oleh PLTU PT. Global Inovasi Prima Growth Asia adalah jenis ketel pipa air Merek TAKUMA N2200 dengan spesifikasi tekanan kerja 46 Bar, temperatur 380oC, dan kapasitas 70 ton/jam. Boiler digunakan untuk pembangkitan listrik 15 MW dengan seluruhnya menggunakan bahan bakar biomassa. Penelitian ini mengkaji nilai efisiensi boiler yang menggunakan tiga jenis biomassa, yang terdiri dari fiber (40,395%), kayu giling (40,569%), dan sekam padi (19,036%)., harga nilai kalor atas atau HHV 19.714 kJ/kg dan nilai kalor bawah atau LHV 17.122,776 kJ/kg. Data pengoperasian boiler yang diperoleh tanggal 21 Juni 2024, menunjukkan tekanan sebesar 34,62 Bar, temperatur 372,62oC, dan kapasitas uap 65,62 ton/jam sehingga diperoleh efisiensi boiler sebesar 58,25%. Efisiensi aktual boiler biomassa lebih rendah dari efisiensi teoritis yang diharapkan berdasarkan data operasional boiler (63,3%) mungkin disebabkan oleh variasi kelembaban bahan bakar yang digunakan.
Identification of flow mark defect on haitian MA 1200 machine in the molding process at PT. Philips Industries Batam Juwita, Erna; Purba, Adi Syahputra; Simanjuntak, Jefri Kemri Rodi Samuel; Br. Manurung, Agnes; Mutiarani, Mutiarani
International Journal of Mechanical Computational and Manufacturing Research Vol. 14 No. 2 (2025): August: Mechanical Computational And Manufacturing Research
Publisher : Trigin Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35335/computational.v14i2.269

Abstract

PT Philips Industries Batam is a company engaged in the manufacturing sector. One of the production processes carried out at PT Philips Industries Batam is the molding process. In the industrial world, the molding process has several types of defects that can affect product quality. The highest number of defects was identified to find the root cause using the Pareto and Fishbone diagram. This research aims to identify the factors causing the defect. Parameters on the Haitian MA 1200 machine were identified to determine the cause of the flow mark defect, thereby improving the quality level of the produced products. From five trials, the optimal parameter setting value was found in the fifth trial. The parameter settings consist of the start post: inject 1 with a value of 63, inject 2 with a value of 42, pressure: inject 1 with a value of 165, inject 2 with a value of 155. Pressure: hold 1 with a value of 55, hold 2 with a value of 45, and flow: hold 1 with a value of 18 and hold 2 with a value of 13. The flow mark defect on the Haitian MA 1200 machine effectively decreased by adjusting certain parameters.
Optimisation of biolubricant synthesis from castor–maggot oil mixture via two-stage transesterification using response surface methodology Mukhriza, Teuku; Hasibuan, Adelia Yesya Putri; Juwita, Erna; Husin, Husni; Silitonga, Arridina Susan
Jurnal Polimesin Vol 24, No 1 (2026): February
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v24i1.8376

Abstract

This study investigates the optimisation and characterisation of a biolubricant produced from a castor–maggot oil mixture via two-stage transesterification. Response surface methodology using a Box–Behnken design was employed to optimise the oil volume ratio, catalyst concentration, and reaction time. The optimum conditions were a castor oil–maggot oil ratio of 50% (v/v), a catalyst concentration of 1% (w/w), and a reaction time of 2 h, resulting in a biolubricant yield of 71.43%. Ethylene vinyl acetate and ethyl-cellulose were added to enhance stability and performance. The biolubricant exhibited a viscosity index of 101.88, kinematic viscosity at 40°C of 54.57 cSt, and a flash point of 235°C, complying with ISO VG 68 and SNI 7069.9:2016 standards. These performance characteristics demonstrate favourable viscosity–temperature behaviour, adequate thermal safety, and suitability for industrial lubrication systems. The integration of mixed vegetable–insect oil feedstocks with Response Surface Methodology (RSM)–Box–Behnken optimisation, together with the incorporation of performance-enhancing additives, resulted in a biodegradable, non-toxic, and environmentally friendly biolubricant that meets standard requirements and shows strong potential as a sustainable alternative to petroleum-based lubricants for mechanical applications.
KARAKTERISTIK BIOOIL DARI ECENG GONDOK SEBAGAI BAHAN BAKAR CAIR MELALUI PROSES PIROLISIS Pratama, Angga Bahri; Juwita, Erna
SINERGI POLMED: Jurnal Ilmiah Teknik Mesin Vol. 7 No. 1 (2026): Edisi Februari
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/sinergipolmed.v7i1.2877

Abstract

Pirolisis eceng gondok (Eichhornia crassipes) adalah proses termokimia yang mengubah biomassa menjadi biooil, arang, dan gas, dengan tujuan menghasilkan bahan bakar alternatif yang lebih ramah lingkungan dibandingkan bahan bakar fosil. Proses ini dilakukan dengan memanaskan eceng gondok pada temperatur 550°C tanpa oksigen, dengan waktu pemanasan sekitar 1 jam. Uap hasil pirolisis dialirkan ke sistem kondensasi untuk didinginkan sehingga mengalami perubahan fase dan menghasilkan biooil sebagai produk utama dalam penelitian ini. Proses pirolisis eceng gondok mampu menghasilkan biooil dengan karakteristik fisik dan kimia seperti densitas 0,981 g/cm³, viskositas (40°C) sebesar 25 mm²/s, titik nyala 120°C, titik tuang –1°C, stabilitas oksidasi 4 jam, bilangan asam 25 mg KOH/g, dan bilangan iodin 80 g I₂/100 g. Penelitian ini menunjukkan bahwa salah satu produk dari pirolisis eceng gondok yaitu biooil memiliki potensi sebagai sumber energi terbarukan yang dapat mengurangi ketergantungan pada bahan bakar fosil, sekaligus memberikan solusi pengelolaan limbah perairan. Akan tetapi, untuk dapat dimanfaatkan lebih jauh sebagai bahan bakar, biooil yang diperoleh dari proses pirolisis ini memerlukan tahapan pemprosesan lanjutan guna meningkatkan kualitasnya sehingga memenuhi standar spesifikasi bahan bakar cair yang berlaku.
Co-Authors Adhe Aryswan Adi Syahputra Purba Andaresta, Windy Angga Bahri Pratama Arridina Susan Silitonga - Bangun, Ary Johanda Cuana, Rona Elvi Zuriyani Hasibuan, Adelia Yesya Putri Husni Husin Manalu, Ari Angga Manurung, Agnes Br. Marbun, Abri Andry Saresa Mutiarani Mutiarani Ritonga, Fatima Sari Rufinus Nainggolan dan Trahman - Simanjuntak, Jefri Kemri Rodi Samuel Surbakti, Benar Teuku Mukhriza Zesa Mulyanda Sari