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Karakteristik temperatur fluida dingin pada grooved double pipe heat exchanger Putu Wijaya Sunu; I Putu Darmawa; Anak Agung Ngurah Bagus Mulawarman; I Made Suarta; I Putu Gede Sopan Rahtika
Jurnal Teknosains Vol 10, No 1 (2020): December
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/teknosains.43291

Abstract

Heat exchangers have widespread applications in many industrials process. There are many kind of heat exchanger. One of the simply heat exchanger is double pipe heat exchanger. The need for lightweight and enhancing the heat transfer of heat exchanger accomodated by surface engineering. One of the surface passive technique applications is groove. Incising groove in pipe as concerned wide consideration as it need no additional power, decrease in weight of system and hence give more benefit in heat transfer. The characteristics of heat transfer in grooved double pipe heat exchanger was investigated experimentally in this article. The aim of this investigation is to reveal the phenomenon of temperature characteristics of cold fluid in the heat transfer process in the grooved double pipe heat exchanger. In this study, water are used as both hot and cold fluid with counter flow pattern, and the water flow rate equal to 15 lpm for both fluid. Grooves were incised on the annulus area in the outer wall of tube side with rectangular shape and circumferential pattern. The characteristics of groove dimension that are height of groove is 0,3 mm; distance between grooves is 8 mm; and the groove space which is as independent variables are 1 mm and 2 mm. The data from 1 mm and 2 mm grooves space were compared with no grooved double pipe heat exchanger data (smooth pipe). The hot fluid temperature is 50 ± 0,50C while the cold fluid temperature is 30 ± 0,50C. The temperature data on the inlet and outlet side of heat exchangers for smooth pipe, 1 mm and 2 mm groove space were compared to find out the characteristics of increasing cold fluid temperature. This study used the temperature rate and temperature acceleration method to compare the variables. The result shows that groove installation increases the amount of heat absorbed by cold fluid. The heat exchanger with 1 mm groove spaces, was able to absorb heat about ± 2.3 % better than heat exchanger with 2 mm groove space and 13,1 % better than heat exchanger with no groove.
The Development of Teaching Material Design for Automotive Electrical and Electronics Laboratorium Based on Automotive-SKKNI to Improve the Achievement of Standar Competencies of Polytechnic Students I Komang Rusmariadi; I Putu Darmawa; I Putu Sastra Negara; Ketut Bangse
Logic : Jurnal Rancang Bangun dan Teknologi Vol 20 No 2 (2020): July
Publisher : Pusat Penelitian dan Pengabdian kepada Masyarakat (P3M) Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31940/logic.v20i2.1639

Abstract

This progress report contains about the achievement of the implementation of the program of research in the development of teaching materials in the form of an integrated jobsheet. The second stage of the development will be done in 2018 with the goal to find: 1) the evaluation result from the expert, lectures, and students, 2)the obstacles during the try out, and 3) the feasibility of the jobsheet draft as a lab teaching material. Research using Dick & Carey development model, in review and test the research involving 2 experts, 7 course lecturerss,and 24 students in mechanical engineering department. Data obtained using questionnaire enclosed and open questionnaire . Data were collected in the form of comments and suggestions as well as the evaluation result toward the integrated jobsheet were analyzed by descriptive qualitative and quantitative improvement. The test results stated: 1) the content expert test is very decent; design / media expert is very decent; individual very decent ; small group is very decent; and field testing of students and lecturer decent and very decent. 2) components that need to be revised from the entire contents of the test results and instructional design experts to field test were:The contents of the summary should be more material-oriented than the summary of jobsheet parts, in addition to trouble shooting ignition problems, it is necessary to add maintenance material that is preventive maintenance, assessment rubrics for evaluation /practical tasks need to be made in more detail from simple to complex practices. Summary and evaluation analysis tools must be clear, the amount of test practice material so that there is a balance of theory and practice, the size of the book should be chosen for an elegant appearance, especially if proposed to ISBN. Based on test data and analysis of the abovementioned, teaching material draft can be declared eligible as the practical of teaching jobsheet. This research only reached the stage of formative evaluation on Jobsheet, it is expected in the future to do more research to determine its effectiveness in an effort to increase the competence of students.
PEMANFAATAN TEKNOLOGI TEPAT GUNA BERUPA MESIN PENCACAH PAKAN TERNAK KAMBING DI DESA SEPANG KABUPATEN BULELENG I Putu Darmawa; I Made Sudana; I Wayan Aryana
Bhakti Persada Jurnal Aplikasi IPTEKS Vol 1 No 1 (2015): November 2015
Publisher : P3M Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (810.893 KB)

Abstract

Kegiatan Pengabdian kepada Masyarakat melalui program Ipteks Bagi Masyarakat bertujuan mengatasi berbagai permasalahan yang dihadapi oleh mitra kelompok peternak kambing Sumber Rejeki dan Tunas Mekar, sehingga dapat meningkatkan produktivitas pakan ternak kambing dan produksi susu kambing. Permasalahan yang dihadapi oleh mitra adalah belum memiliki mesin pencacah pakan ternak, sehingga pada saat musim kemarau sangat sulit mendapatkan pakan ternak, Penerapan teknologi tepat guna pada proses pengolahan pakan ternak berupa ranting lantoro, gamal, dan berupa daun. Sebelum program dilaksanakan peternak kambing dapat memotong pakan ternak sebanyak 40-50 kg/hari. Setelah program dilaksanakan dengan penerapan mesin pemotong ranting untuk pakan ternak ada peningkatan hasil pakan ternak sebesar 60-90 kg/hari dengan hasil cacahan 1-3cm, untuk menjaga kebutuhan pakan ternak dimusim kemarau dilakukan Fermentasi pakan dengan menggunakan drum plastik kapasitas 25 kg. Hasil pelaksanaan program IbM pada Kelompok mitra yaitu 1.Memiliki mesin pencacah pakan ternak. 2. Mempunyai sarana pengoloahan pakan ternak dengan sistem Fermentasi. Dengan adanya sarana tersebut, anggota mitra merasa terbantu dalam mengatasi pengolahan pakan ternak yang mereka hadapi oleh kelompok Ternak Sumber Rejeki dan Ternak Tunas Mekar,”menjadi lebih bersemangat dalam mengembangkan usahanya
PENGUJIAN ARAK BALI SEBAGAI ADITIF BAHAN BAKAR I Made Suarta; I Putu Darmawa
Industri Inovatif : Jurnal Teknik Industri Vol 6 No 2 (2016): inovatif Vol. 6 No. 2
Publisher : Prodi Teknik Industri S1 Institut Teknologi Nasional Malang

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

Abstract

Arak diperoleh dari penyulingan tuak (nira) dari pohon rontal, enau atau kelapa yang mempunyai sifat mudah terbakar (flameable). Arak adalah etanol, jika proses penyulingan dengan temperatur 78,1oC menghasilkan arak (etanol) dengan kadar lebih tinggi yang sering disebut arak api di Bali. Secara teoritis proses penyulingan akan menghasilkan arak dengan kadar maksimum 95,5% yang sering disebut etanol azeotrop. Langkah pertama yang dilakukan dalam pengujian arak bali sebagai bahan bakar adalah pengujian terhadap kadar air. Pengujian kadar air arak bali hasil Laboratorium Kimia adalah 70% atau etanol 30%. Selanjutnya dilakukan distilasi lanjutan untuk mengurangi kadar air sampai komposisi azeotrope. Pengujian kecepatan pembakaran arak bali dilakukan dalam ruang bakar cylinder show shell. Proses pembakaran direkam menggunakan kamera kecepan 420 fps. Hasilnya menunjukkan bahwa kecepatan pembakaran arak bali komposisi azotrope lebih tinggi dari etanol 99% pada campuran stoichiometri dan kaya.
Cutting Speed Analysis of Organic Waste Chopping Machine Fly Wheel Model Level Control I Putu Darmawa; I Nengah Ludra Antara; I Nyoman Sutarna; Ida Bagus Puspa Indra; I Nyoman Gunung
Logic : Jurnal Rancang Bangun dan Teknologi Vol. 23 No. 2 (2023): July
Publisher : Unit Publikasi Ilmiah, P3M, Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31940/logic.v23i2.121-130

Abstract

This machine is used to chop leaves, twigs and branches into very small pieces, to avoid the bad smell due to the decay of organic waste and can be used as compost. The amount of cutting speed on the organic waste chopping machine with a chopping time of 2.5 kg of ketapang leaves is the average time obtained without fly wheels 2.0 minutes and with fly wheels 1.7 minutes, a time difference of 0.3 minutes. The chopping time of 2.5 kg of ketapang branches with an average time obtained without a fly wheel of 2.2 minutes and with a fly wheel of 2.0 minutes, a time difference of 0.2 minutes. The chopping time of teak branches is 2.5 kg with an average time obtained without a fly wheel of 2.6 minutes and with a fly wheel of 2.0 minutes, so the time difference is 0.6 minutes. So the cutting speed using a fly wheel is better. The results of the productivity obtained on the organic waste chopping machine, for the results of leaf chopping productivity without a fly wheel of 48% and those using a fly wheel of 58%, and the results of leaf chopping with a fly wheel are 10% more productive, for the productivity of chopping twigs without a fly wheel of 44% and those using a fly wheel of 49%, so the results of chopping twigs with a fly wheel are 5% more productive, and the results of chopping branches without a fly wheel of 37% and those using a fly wheel of 49%, so the results of chopping branches with a fly wheel are 12% more productive.