Articles
<![CDATA[Pengaruh Perlakuan Alkali Terhadap Kekuatan Tarik dan Wettability Serat Alam Agave Sisalana Perrine ]]>
<![CDATA[Ferriawan Yudhanto]]>;
<![CDATA[Andika Wisnujati]]>;
<![CDATA[Kusmo no]]>
<![CDATA[ Retii Prosiding Seminar Nasional ReTII ke-11 2016 ]]>
Publisher : <![CDATA[Institut Teknologi Nasional Yogyakarta ]]>
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<![CDATA[Penelitian ini membahas tentang sifat mekanis dan kemampuan matriks membasahi serat (wettability) serat sisal (agave sisalana perrine) akibat perendaman alkali (NaOH) konsentrasi 5% dengan jangka waktu 0, 2, 4, 6 dan 8 jam. Matriks yang digunakan yaitu unsaturated polyester (UPR) ditambah dengan methyl-ethyl-keton peroxide (Mekpo) sebagai katalis. Perendaman mengakibatkan hilangnya lapisan wax pada serat sisal sehingga mengakibatkan meningkatnya kekasaran permukaan (surface roughness) pada serat dan juga menaikkan nilai indeks kristalinitas (crystallinity index) selulosa serat sisal. Kedua hal ini akan meningkatkan ikatan interfacial bonding antara serat dan matriks. Bentuk dari droplet UPR pada uji wettability selama perendaman alkali 4 jam posisi droplet cenderung berbentuk barrel yang memiliki sudut kontak 10o<θ<29o, hal ini menunjukkan bahwa terjadi tegangan permukaan yang baik antara serat dan matriks. Sedangkan perendaman serat dalam waktu yang lama yaitu 6 dan 8 jam akan membentuk droplet dengan bentuk geometri clam-shell yang memiliki sudut kontak 45o<θ<64o, hal ini mununjukkan bahwa serat sisal telah rusak dan mengakibatkan rendahnya ikatan interfacial bonding antara serat dan matriks. Pengujian mekanis menggunakan Universal Testing Machine juga menunjukkan hasil peningkatan kekuatan tarik (tensile strength) dan modulus elastisitas akibat naiknya indeks kristalinitas selulosa di dalam serat sisal pada perlakuan alkali selama 4 jam.Kata Kunci : serat sisal, tensile strength, wettability]]>
<![CDATA[KARAKTERISASI LAPISAN OKSIDA HASIL ANODIZING PADA ALUMINIUM DENGAN VARIABEL WAKTU PENCELUPAN ]]>
<![CDATA[Andika Wisnujati]]>;
<![CDATA[Ferriawan Yudhanto]]>
<![CDATA[ Jurnal Rekayasa Mesin Vol. 14 No. 2 (2023) ]]>
Publisher : <![CDATA[Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya ]]>
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DOI: 10.21776/jrm.v14i2.1309
<![CDATA[Anodizing is an electrolytic coating process that converts aluminum into aluminum oxide. The anodizing process is widely used in the manufacturing industry, especially in automotive components. Its utilization has benefits such as resistance to scratches, ease of maintenance, and added decorative value. The purpose of this study was to determine the effect of time variations on the hardness and thickness of the oxide layer in the 6xxx series of aluminum anodizing processes. The variation of time used in the immersion process is 20, 30, and 40 minutes, with an electric current of 2 amps and a voltage of 24 volts. After that, the dyeing and sealing process is carried out. The tests carried out included testing of hardness (Vickers) and the thickness of the oxide layer (coating thickness gauge). The results of the highest hardness test of 112.9 VHN were obtained at a time variation of 40 minutes, with an average layer thickness of 5.07 m. It can be said that the amount of time spent in the anodizing process has an effect on how hard the oxide layer gets and how thick it is on the 6xxx series of aluminum metal. Â ]]>
<![CDATA[Design and stress analysis of adjustable chair on handcycle for persons with disabilities ]]>
<![CDATA[Andika Wisnujati]]>
<![CDATA[ Jurnal POLIMESIN Vol 20, No 2 (2022): August ]]>
Publisher : <![CDATA[Politeknik Negeri Lhokseumawe ]]>
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DOI: 10.30811/jpl.v20i2.3013
<![CDATA[Handcycle is one of bicycle that used by someone with physical limitations, and this bicycle is operated by hand. Some people who have physical limitations will not be able to ride a bicycle in general, so a handcycle is made using three wheels to be able to maintain the balance of the rider's body. This handcycle is a solution for people with disabilities to be able to go somewhere and also exercise. In this study, an adjustable chair design was made that is suitable for handcycles and has an adjustable function, namely making the handcycle seat move forward or backward to make it easier for a rider to adjust the position of the legs in moving the handcycle. The material used to manufacture the adjustable chair on the handcycle is iron plate, which is an elbow-shaped iron plate with an angle of 90o. The length is 300 mm, width 200 mm and thickness 50 mm. After the design is made, then a stress analysis test with Autodesk Inventor 2016 is carried out on the adjustable chair on the handcycle by analyzing the strength of the chair and also the appropriate body posture when supporting the weight of a person with a disability. The final result of the adjustable chair applied to the handcycle was measured by stress analysis using Autodesk Inventor 2016 software. The material strength (Von Misess) for male users who weighs 70 kg has a maximum value of 1.767 MPa with a maximum displacement of 0.0059. As for female users weighing 60 kg, the maximum value is 1.514 MPa with a maximum displacement of 0.050.]]>
<![CDATA[Delta EC Simulation on Influence of Resonator Length in Close-Open Standing Wave Thermoacoustic Engine ]]>
<![CDATA[Anugrah, Rinasa Agistya]]>;
<![CDATA[Wisnujati, Andika]]>;
<![CDATA[Anggara, Fajar]]>
<![CDATA[ Jurnal Engine: Energi, Manufaktur, dan Material Vol. 7 No. 2 (2023) ]]>
Publisher : <![CDATA[Proklamasi 45 University ]]>
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DOI: 10.30588/jeemm.v7i2.1501
<![CDATA[Many applications of thermoacoustic engines in engineering. With its pressure of it, the energy can be harvested and can be converted to many other needs of energies like electrical energy. Energy in thermal form is converted to become acoustic energy and subsequently used to activate a bidirectional turbine. The resonator is very influential toward the power of the thermoacoustic engines. Simulation study with Delta EC fit to make predictions acoustic power as representative performance in thermoacoustic engine with close-open type and standing wave of oscillation. In this study, the material of the resonator is made from a stainless-steel duct with a diameter size of 50.8 mm with three variations of the length. The Standing-Wave Thermoacoustic Engine (SWTE) generates acoustic energy from a temperature gradient of 315 – 993 K. In this simulation, Acoustic Power decreased when the resonator length was extended. The shortest resonator had an acoustic power of 50.4 W, and the longest resonator had an acoustic power of 35.7 W.]]>
<![CDATA[CHARACTERIZATION OF CENTRIFUGAL CASTING METHOD FOR PULLEY MANUFACTURING USING VARIABLE ROTATIONAL SPEED ]]>
<![CDATA[Wisnujati, Andika]]>;
<![CDATA[Shomad, Muhammad Abdus]]>
<![CDATA[ Media Mesin: Majalah Teknik Mesin Vol. 25 No. 2 (2024) ]]>
Publisher : <![CDATA[Universitas Muhammadiyah Surakarta ]]>
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DOI: 10.23917/mesin.v25i2.2374
<![CDATA[Due to advancements in the industrial sector, aluminum is progressively gaining popularity as a material of choice in the field of engineering. A pulley is a component that functions as a link or transfers power or engine rotation to the load via the V-belt belt. This study aims to determine the characterization of aluminum material made by the centrifugal casting method from used brake shoes with rotational speed variables of 0 RPM, 100 RPM, and 200 RPM. The characterization of the casting results in this study was analyzed using the Brinell hardness test and the Charpy impact test. The results of the Brinell hardness test showed that aluminum castings for making pulleys with an additional 100 RPM die rotation speed had a Brinell hardness value of 53.22 BHN. The results of the impact test with the Charpy method showed that specimens with a mold rotation speed of 100 RPM had an impact value of 0.0135 kg.m/mm2. The results of this study concluded that variations in rotational speed of 100 RPM in the casting of pulleys made of used aluminum using the centrifugal casting method can produce products that have good toughness.]]>
<![CDATA[Hydrosmart: Sistem Otomatisasi Penyiraman Tanaman Hidroponik ]]>
<![CDATA[Wibawa, Unggul Adi]]>;
<![CDATA[Indah, Diyaah Putri]]>;
<![CDATA[Nurmayanti, Septia]]>;
<![CDATA[Putri, Saskia Maharani]]>;
<![CDATA[Zahira, Zalfa Shafa’]]>;
<![CDATA[Putra, Zebadia Akbar]]>;
<![CDATA[Zen, Andril Muhammad]]>;
<![CDATA[Zalzabilla, Alifvia Kityn]]>;
<![CDATA[Nuki, Fauzan Rizky]]>;
<![CDATA[Fauzi, M. As’ad]]>;
<![CDATA[Wisnujati, Andika]]>
<![CDATA[ Prosiding Seminar Nasional Program Pengabdian Masyarakat Vol. 8 No. 1 (2025): Rekonstruksi Pendidikan di Indonesia ]]>
Publisher : <![CDATA[Universitas Muhammadiyah Yogyakarta ]]>
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DOI: 10.18196/ppm.81.1301
<![CDATA[Donorojo Village, Donorojo District, Pacitan has great potential in hydroponic cultivation as an alternative to sustainable agriculture. However, the main challenges faced by farmers are the efficiency of watering and optimal monitoring of plant nutrients. To overcome this problem, this community service activity presents Hydrosmart, a hydroponic plant watering automation system based on Internet of Things (IoT) technology. This system is designed to optimize the use of water and nutrients with humidity sensors and automatic control based on microcontrollers. The purpose of this program was to enhance the knowledge and skills of using technology for sustainable agriculture. The methods used in this program include training and mentoring for hydroponic farmers in designing, operating, and maintaining the Hydrosmart system. In addition, an implementation trial was conducted on a pilot area to measure the effectiveness of the system in increasing watering efficiency and plant productivity. This activity was an innovative solution for hydroponic farmers in Donorojo in increasing agricultural yields more efficiently and sustainably. In addition, the implementation of this technology also had the potential to improve farmer welfare through resource efficiency and increased production. By implemented Hydrosmart, the people of Donorojo Village are expected to be more prepared to face the challenges of modern technology-based agriculture]]>
<![CDATA[Pemberdayaan Kepala Dusun Desa Belah Melalui Program Pelatihan Dasar Penggunaan Microsoft Word ]]>
<![CDATA[Ghani, Farid Abdul]]>;
<![CDATA[Acyutarayi, Rakashafi Noorsy]]>;
<![CDATA[Putri, Kika Fidiyah]]>;
<![CDATA[Khotimah, Khusnul]]>;
<![CDATA[Dini, Putri Indra]]>;
<![CDATA[Widhaningrum, Tivani Nuri]]>;
<![CDATA[Adhitya, Fajar]]>;
<![CDATA[Marjani, Zaidan Isham]]>;
<![CDATA[Hanani, Hayyu Amalina]]>;
<![CDATA[Tsany, Dylan Ataa]]>;
<![CDATA[Wisnujati, Andika]]>
<![CDATA[ Prosiding Seminar Nasional Program Pengabdian Masyarakat Vol. 8 No. 1 (2025): Rekonstruksi Pendidikan di Indonesia ]]>
Publisher : <![CDATA[Universitas Muhammadiyah Yogyakarta ]]>
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DOI: 10.18196/ppm.81.1320
<![CDATA[Increasing the capacity of village officials in the use of information technology is a strategic step in accelerating village government administration. Hamlet heads, as part of the village apparatus, need to have basic skills in digital document management in order to improve work efficiency. This basic Microsoft Word training program aims to empower hamlet heads in Belah Village, Donorojo District, Pacitan, by providing understanding and practical skills in creating and managing documents. This training was attended by 12 participants and used practice-based learning methods, interactive discussions, and direct assistance. Evaluation was carried out through a survey of participants to measure the effectiveness of the training. The survey results showed that 83% of participants felt that their skills had improved significantly, especially in the use of basic Microsoft Word features such as text formatting, table creation, and image insertion. As many as 75% of participants stated that this training was very relevant to their administrative tasks, while 92% expressed interest in taking further training. These results indicate that the training program has a positive impact on improving the competence of hamlet heads in document management. It is hoped that the sustainability of this program can support more effective and efficient village administration]]>
<![CDATA[ANALISIS PERLAKUAN CARBURIZING TERHADAP SIFAT FISIK DAN MEKANIK PADA BAHAN SPROCKET IMITASI SEPEDA MOTOR ]]>
<![CDATA[Wisnujati, Andika]]>
<![CDATA[ Simetris: Jurnal Teknik Mesin, Elektro dan Ilmu Komputer Vol 8, No 1 (2017): JURNAL SIMETRIS VOLUME 8 NO 1 TAHUN 2017 ]]>
Publisher : <![CDATA[Fakultas Teknik Universitas Muria Kudus ]]>
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DOI: 10.24176/simet.v8i1.844
<![CDATA[Kemajuan industri dan teknologi semakin berkembang pesat, termasuk industri logam. Kemajuan industri logam memiliki peranan yang penting terutama dalam dunia otomotif yang banyak menggunakan material dari logam. Sprocket merupakan komponen utama dalam sepeda motor, sebagai transfer gaya putar dari mesin menuju ke roda, sehingga akan cepat aus karena akan terjadi gesekan antara rantai dengan gear pada waktu mentransfer gaya putar dari mesin. Pada penelitian ini sprocket mengalami proses carburizing (karbonisasi) yaitu proses memanaskan bahan sampai diatas suhu kritis 900⁰C-950⁰C dengan penahanan selama 1 (satu) jamkemudian didinginkan dengan media air. Carburizingbertujuan memberikan kandungan karbon lebih banyak pada bagian permukaan dibanding dengan bagian inti benda kerja, sehingga kekerasan permukaan diharapkan dapat meningkat.Hasil pengujian kekerasan sprocket imitasi didapat nilai kekerasan rata-rata 219.23 VHN dan sprocket genuine tanpa perlakuan panas yaitu sebesar 217.68VHN. Hal ini dikarenakan pada sprocket imitasi terdapat kandungan kadar karbon dan silikon lebih besar setelah dilakukan carburizing.Hasil pengujian struktur mikro pada sprocket imitasi, struktur ferrit terbentuk dari proses pendinginan yang lambat dari austenit (baja hypoeutectoid)dan mempunyai konduktivitas panas yang tinggi sehingga struktur ini bersifat lunak serta ulet. Pada fasa struktur perlite terbentuk campuran antara ferit dan sementit. Pada 0,8% karbon perlit yang tampak seperti pelat-pelat yang tersusun secara bergantian oleh perpaduan struktur antara struktur ferrit dan sementit, serta fasa struktur ini memiliki sifat ulet dan kekerasan yang cukup tinggi, kemudian sturktur mikro sementit senyawa besi karbon (Fe3C) bersifat keras pada pendinginan lambat bentuknya lamellar bersifat keras.]]>
<![CDATA[Experimental Study of Drying Fruits and Vegetables Using The Freeze Drying Method With The Aim of Maintaining The Nutrition and Effectiveness of Processed Products ]]>
<![CDATA[Yusuf, Mirza]]>;
<![CDATA[Nulhakim, Lukman]]>;
<![CDATA[Prambandono, Bayu]]>;
<![CDATA[Wisnujati, Andika]]>;
<![CDATA[Yudhanto, Ferriawan]]>
<![CDATA[ Quantum Teknika : Jurnal Teknik Mesin Terapan Vol. 6 No. 2 (2025): April ]]>
Publisher : <![CDATA[Universitas Muhammadiyah Yogyakarta ]]>
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DOI: 10.18196/jqt.v6i2.24507
<![CDATA[The potential of natural resources in tropical countries is very diverse. one of them is the abundant agricultural products. but there are some obstacles in the post-harvest cycle and the continuous availability when the harvest season ends. various methods of preserving agricultural products have been tested from conventional methods to advanced technology. one of the technologies for preserving agricultural products is freeze drying. various innovations continue to be tested until they get consistent results with good energy efficiency. This method was originally started in the pharmaceutical industry. Various treatments and flexible adaptations make this method penetrate the food industry to maintain the quality of food products. In the food industry, freeze drying is suitable for food products such as meat, fruits, grains, and vegetables. The advantage of freeze drying is that the food products produced do not change shape, form, texture, taste, and nutrition even though they have gone through the drying process. Of the various characteristics of fruits and vegetables have their own properties that can be changed with the temperature parameters applied in the freeze dryer method.]]>
<![CDATA[2D Modelling of the Breakdown Voltage of Hybrid Dielectric (Gas and Solid) System ]]>
<![CDATA[Muzamil, Sanupal]]>;
<![CDATA[Wisnujati, Andika]]>
<![CDATA[ Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi Vol 11 No 2 (2025): August ]]>
Publisher : <![CDATA[Universitas Sarjanawiyata Tamansiswa ]]>
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DOI: 10.30738/st.vol11.no2.a19380
<![CDATA[Sulfur hexafluoride (SF6) has been used over decades due to its excellent dielectric, arc quenching and heat transfer properties, but has tremendous global warming potential. It is therefore mandatory to find more environmentally friendly alternatives by designing of future eco-friendly hybrid insulation (solid and gas) system that require a thorough understanding of the evolution of electric field in such structure. A numerical model was developed using finite element method (FEM) of a commercial software Comsol® Multiphysics. Using electrostatic equations, the 2D model stability, 2D boundary model and voltages are varied in order to identify their influence on the electric field distribution. Numerical simulations show that maximum electric fields will vary significantly according to distances of point-dielectric (gap). The maximum electric field increases if the gap (electrode tip-planar) size is shorter. Additionally, the electric field is not linearly spread in solid dielectric material and more concentrated around the edges of solid dielectric.]]>
