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PENANGANAN BERBAGAI TINGKAT KELENGKETAN PADA ALAT GELAS DI LABORATORIUM DARI PENGARUH BASA KUAT LARUTAN NAOH BESERTA UJINYA Harjanto, Sri; Gunawan, Indra
Jurnal Pengelolaan Laboratorium Pendidikan Vol. 2, No. 1, Januari 2020
Publisher : Laboratorium Bio Teknologi, Fakultas Sains dan Matematika, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (717.345 KB) | DOI: 10.14710/jplp.2.1.19-25

Abstract

As PLP (Educational Laboratory Institution) or other laboratory personnel for their daily work, they are very closely related to the tools and materials in the laboratory scope, and cannot be separated from laboratory equipment in the form of instruments or glassware. The problem here is that there are times when we encounter glassware in the scope of a laboratory whose faucet is closed or the faucet cannot be opened because it is sticky, and on average it is used after using NaOH base solution. That is why we are here to try to do a test to find out how much the stickiness of a device made from glass raw materials. By using variable various levels of concentration of NaOH solution with different time periods. As a decay the detergent solution is also used in various levels of concentration and heating. . From the data of the stickiness level test results using variable concentrations of NaOH solution and detergent solution will get the results that with the increasing concentration of NaOH solution, the stickiness will also be stronger. Likewise with the passage of time the longer the NaOH solution comes into contact with materials made of glass, the harder it will become and the stickiness will also be stronger so that it will be more difficult to be released. while on a strong adhesiveness will be more effective when using the immersion method at a temperature of 60-70 ° C.
Peran Laminar Air Flow Cabinet Dalam Uji Mikroorganisme Bagi Mahasiswa Tugas Akhir Di Laboratorium Biokimia Harjanto, Sri; Raharjo, R
Jurnal Pengelolaan Laboratorium Pendidikan Vol. 1, No. 1, Januari 2019
Publisher : Laboratorium Bio Teknologi, Fakultas Sains dan Matematika, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (69.704 KB) | DOI: 10.14710/jplp.1.1.15-18

Abstract

Work safety and security in the laboratory environment is very much needed, especially those related to microorganisms. In this case the purpose of the survey is to find out what percentage of the success rate of inoculation or the planting of microorganisms using the Laminar Air Flow instrument. As for the method used based on the classification survey of the number of tools used. And from the observation / survey that the number of users of laminar water flow in the Biochemistry laboratory for 1 year (2017) shows a very significant number especially in certain months such as October - November reached 27, 31 users, overall the number of users was quite large. This means that the instrument is needed for its existence. Also from the types of activities carried out by the Final Project students so far by using these instruments can be well served means that the tool is able to help solve problems of students who are completing their research.
PERAN LAMINAR AIR FLOW CABINET DALAM UJI MIKROORGANISME UNTUK MENUNJANG KESELAMATAN KERJA MAHASISWA DI LABORATORIUM MIKROBIOLOGI Harjanto, Sri; Raharjo, Raharjo
METANA Vol 13, No 2 (2017): Desember 2017
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (977.466 KB) | DOI: 10.14710/metana.v13i2.18016

Abstract

Keamanan dan keselamatan kerja di lingkungan laboratorium sangat dibutuhkan , seperti di laboratorium mikrobiologi. Untuk menunjang hal tersebut di atas peran Laminar air flow cabinet dirasa sangat penting akan keberadaannya karena mempunyai tingkat keamana dan keselamatan bagi pemakai yang lebih tinggi dibandingkan jika kita masih menggunakan peralatan sederhana seperti inkas. Lebih ?lebih untuk penanganan bakteri yang bersifat patogen. Di laboratorium mikrobiologi ini melayani mahasiswa yang mengambil mata kuliah praktikum pendidikan juga mahasiswa yang sedang menyelesaikan penelitian Tugas Akhir. Dengan Laminar air flow cabinet ini didukung kedisiplinan serta bekerja sesuai peraturan tata tertib yang ada    diharapkan  bisa membantu menyelesaikan tugas dan bisa memberikan perlindungan serta  rasa aman bagi  mahasiswa tersebut. The role of  laminar air flow cabinet in the test of microorganism to presurve work safetyin student microbiology laboratory  Safety and safety in the laboratory environment is needed, as in the microbiology laboratory. To support the above, the role of Laminar air flow cabinet feels very important to its existence because it has a level of security and safety for users who are higher than if we still use simple equipment such as inkas. More-for the handling of bacteria that are pathogenic. In this microbiology laboratory serves students who take courses of educational practicum as well as students who are completing research Final Assignment. With Laminar air flow cabinet is supported by discipline and work according to existing rules of order are expected to help complete the task and can provide protection and a sense of security for the student. 
MORFOLOGI DAN KARAKTERISTIK LAPISAN INTERMETALIK AKIBAT DIE SOLDERING PADA PERMUKAAN BAJA CETAKAN (DIES) DALAM PROSES PENGECORAN TEKAN PADUAN ALUMINIUM SILIKON Suharno, Bambang; Dimiyati, Rima; Arifin, Bustanul; Harjanto, Sri
Jurnal Teknik Mesin Vol 9, No 2 (2007): OCTOBER 2007
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (405.02 KB) | DOI: 10.9744/jtm.9.2.

Abstract

The major mode which lead to die failure in die casting is die soldering caused by the intimate contact between alloy and die at high temperature. It leads to malfunctioning of die inserts that require replacement or repair, thus causing significant decrease in productivity. The effect of melt temperatures on morphology and characteristic of intermetallic layer such as thickness and hardness of intermetallic layer between die surface and aluminum has been studied. This experiment used as-annealed H13 tool steel as die material which dipped into Al-7%Si alloy at 6800C, 7000C, 7200C and Al-11%Si alloy at 6600C, 6800C, 7000C. High melt temperature favored the growth of intermetallic layer due tp the increasie of the diffusion rate of iron and aluminum atoms. Hence, high melt temperature facilitates die soldering. Abstract in Bahasa Indonesia: Umumnya kerusakan cetakan pada industri die casting disebabkan die soldering yang terjadi pada permukaan cetakan yang mengalami kontak langsung dengan logam cair pada temperatur tinggi. Hal ini dapat menyebabkan perlu diadakannya perbaikan atau penggantian cetakan sehingga menurunkan produktivitas. Untuk itu dilakukan penelitian mengenai pengaruh temperatur logam cair (melt) terhadap morfologi dan karakteristik lapisan intermetalik yaitu ketebalan dan kekerasan lapisan intermetalik yang terbentuk antara permukaan cetakan dan logam cair. Pada penelitian ini digunakan baja H13 as annealed sebagai material cetakan yang dicelup ke dalam paduan Al-7%Si pada temperatur 6800C, 7000C, 7200C dan Al-11%Si pada temperatur 6600C, 6800C, 7000C. Peningkatan temperatur logam cair akan meningkatkan laju difusi pertumbuhan lapisan intermetalik karena laju difusi atom-atom besi dan aluminium meningkat. Sehingga ketebalan dari lapisan intermetalik akan meningkat seiring dengan peningkatan temperatur logam cair. Oleh sebab itu, tinggiya temperatur logam cair memper¬mudahkan terjadinya die soldering. Kata kunci: Die casting, die soldering, paduan aluminium silikon, temperatur logam cair, lapisan intermetalik.
PENANGANAN ALAT DAN BAHAN YANG BAIK DALAM RANGKA MENUNJANG KEGIATAN DI LABORATORIUM KIMIA Raharjo, Raharjo; Harjanto, Sri
METANA Vol 13, No 2 (2017): Desember 2017
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (955.433 KB) | DOI: 10.14710/metana.v13i2.18017

Abstract

Fasilitas alat dan bahan di lingkungan laboratorium kimia bagi mahasiswa yang sedang menyelesaikan tugas penelitian merupakan suatu hal yang tidak bisa terpisahkan, dan sangat diperlukan keberadaanya. Maka  sistem kelola, cara penanganan dengan  baik dan benar terutama  yang berhubungan dengan bahan kimia ataupun alat gelas dan instrumen mulai dari proses pengadaan, penerimaan , pengemasan, penyimpanan sampai penyaluran, penggunaan sesuai dengan tata kelola yang baik dan benar, juga ditunjang pelayanan yang memadai akan sangat membantu dalam rangka penyelesaian kegiatan penelitian mahasiswa Tugas Akhir di laboratorium kimia. Handling of good equipments and materials to order to supply activities studensts at the chemical laboratory  Equipment and materials facilities in chemical laboratory environment for students who are completing research tasks is an inseparable, and indispensable condition. Therefore, good and proper handling system, especially those related to chemicals or glassware and instruments starting from the procurement, receiving, packaging, storage until distribution, use in accordance with good and correct governance, also supported by adequate services will very helpful in the completion of research activities of Final Final students in the chemistry laboratory.
THE INFLUENCE OF GRAIN REFINER ON DENDRITE ARM SPACING OF ALUMINUM ALLOY ADC 12 Suharno, Bambang; Nanda, Is Prima; Harjanto, Sri; Lirachandra, Erika
Jurnal Sains Materi Indonesia Vol 8, No 2: FEBRUARI 2007
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (414.608 KB) | DOI: 10.17146/jsmi.2007.8.2.4776

Abstract

THE INFLUENCE OF GRAIN REFINER ON DENDRITE ARM SPACING OF ALUMINUM ALLOY ADC 12. ADC 12 is the common used materials for die casting process in producing automotive components. Grain refiner was added to aluminum ADC 12 to increase mechanical properties by decreasing grain size and improving fine distribution of gas porosity. Grain refiner also give positive effect in aluminum fluidity, where the proper addition of grain refiner will increase the fluidity. The purpose of present research is determining correlation between grain refiner addition and dendrite arm spacing, which also indirectly related to the grain size. 100% scrap of aluminum ADC12 and Al5Ti1B grain refiner were used as raw materials. Melting process has been done in a 1400 gr crucible with cokes and oxygen as the fuming energy. Argon was introduced into crucible at least in 1 minute for degassing. After degassing process accomplished, 0, 0.05, 0.1, 0.15, 0.2 % grain refiner Al5TiB, which have been choosen as experimental variable, were charged into crucible. Vacuum suction machine has been utilized to measure the aluminum fluidity at 680 0C, the common ADC 12 pouring temperature. Samples for microstructural analysis were tooken at the tip of specimen from vacuum suction test. Measurement of dendrite arm spacing (DAS) was conducted by SIGMA SCAN Pro.5 Software. The result indicated that at 680 0C, the addition up to 0.15% Al5Ti1B grain refinement reduced 50% dendrite arm spacing from 8.8 ìm (without grain refiner) to 4.5 ìm. Over 0.15% Al5Ti1B, the refinement stopped and DAS increased caused by the complex intermetallic phase (Ti-Al, Ti-B) has nucleated from the excess grain refiner.
PENGARUH PROFITABILITAS, LIKUIDITAS, KEPEMILIKAN SAHAM PUBLIK DAN UMUR LISTING TERHADAP VOLUNTARY DISCLOSURE PADA PERUSAHAAN MANUFAKTUR DI INDONESIA Aulya, Duroriyatul; -, Sutono; Harjanto, Sri
Jurnal Dinamika Manajemen (Journal of Management Dynamics) Proceeding Madic 2015
Publisher : Department of Management, Faculty of Economics, Semarang State University, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/jdm.v0i0.4795

Abstract

Effect of Contact Time on Interface Reaction between Aluminum Silicon (7% and 11%) Alloy and Steel Dies SKD 61 Suharno, Bambang; Nurhayati, Neni; Arifin, Bustanul; Harjanto, Sri
Makara Journal of Technology Vol 11, No 2 (2007)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (355.121 KB) | DOI: 10.7454/mst.v11i2.132

Abstract

Die soldering (die sticking) is a defect of metal casting in which molten metal “welds” to the metallic die mold surface during casting process. Die soldering is the result of an interface reaction between the molten aluminum and the die material. Aluminum alloy with 7 and 11% silicon and SKD 61 die steel are the most common melt and die material used in aluminum die casting. This research is done to study the morphology and the characteristics of the formed AlxFeySiz intermetallic layer during interface reaction at dipping test. The samples of as-anneal SKD 61 tool steel was dipped into the molten of Al-7%Si held at temperature 680oC and into molten Al-11%Si held at temperature 710oC with the different contact time of 10 minutes; 30 minutes; and 50 minutes. The research results showed that the interface reaction can form a compact intermetallic layer with AlxFey phase and a broken intermetallic layer with AlxFeySiz phase on the surface of SKD 61 tool steel. The increasing of the contact time by the immersion of material SKD 61 tool steel in both of molten Al-7%Si and Al-11%Si will increase the thickness of the AlxFeySiz intermetallic layer until an optimum point and then decreasing. The micro hardness of the AlxFeySiz intermetallic layer depends on the content of the iron. Increasing of the iron content in intermetallic layer will increase the micro hardness of the AlxFeySiz. This condition happened because the increasing of Fe content will cause forming of intermetallic AlxFeySiz phase becomes quicker.
Peran Laminar Air Flow Cabinet Dalam Uji Mikroorganisme Bagi Mahasiswa Tugas Akhir Di Laboratorium Biokimia Harjanto, Sri; Raharjo, R
Jurnal Pengelolaan Laboratorium Pendidikan Vol. 1, No. 1, Januari 2019
Publisher : Jurnal Pengelolaan Laboratorium Pendidikan

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

Abstract

Work safety and safety in the laboratory environment is needed. Based on the method of classification of the number of appliances usage. In this case from the observation / survey that the number of users of Laminar air flow in biochemical laboratories for 1 year (2017) this shows a very significant number, especially in certain months such as October - November reached the number 27, 31 users, the overall number of users enough many. This means showing that the instrument is needed for its existence.Also from the type of activities undertaken by students of Final Project so far by using these instruments can be served well means the tool is able to help solve the problems of students who are completing the research. Keywords: Microorganism, Laminar Air Flow, Safety
Pemanfaatan Karbon Biomassa sebagai Reduktor dalam Ekstraksi Fe-Ni dari Bijih Nikel Laterit Abidin, Faizinal; Harjanto, Sri; Kawigraha, Aji; P, Nur Vita
Prosiding Seminar Nasional Teknoka Vol 3 (2018): Prosiding Seminar Nasional Teknoka ke - 3
Publisher : Fakultas Teknik, Universitas Muhammadiyah Prof. Dr. Hamka, Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (385.151 KB) | DOI: 10.22236/teknoka.v3i0.2901

Abstract

Pada proses pengolahan bijih nikel laterit, kokas dan agen reduktor lain diperlukan sebagai bahan utama sumber karbon untuk mereduksi senyawa oksida dalam laterit. Salah satu alternatif untuk mengganti ketergantungan reduktor konvensional adalah karbon biomassa yang memiliki potensi untuk dijadikan sumber reduktor berkelanjutan. Dalam penelitian ini akan dilakukan proses reduksi langsung terhadap bijih nikel laterit untuk mendapatkan recovery besi dan nikel dengan menggunakan arang batok kelapa sebagai reduktor karbon biomassa. Reduksi dilakukan pada temperatur 1200OC ditahan 90 menit, pemanasan dilanjutkan sampai 1500OC dan ditahan 15 menit. Variasi penambahan arang batok kelapa yang digunakan adalah 25%, 37.5% dan 45% massa. Selain itu ditambahkan 10% CaCO3 untuk menurunkan titik lebur dan mengasilkan recovery Fe-Ni yang lebih tinggi. Uji komposisi kimia dilakukan pada bijih nikel laterit dan hasil reduksi untuk mengetahui recovery besi dan nikel. Analisa mineralogi dan karakterisasi struktur mikro untuk menganalisis pemetaan morfologi permukaan nikel laterit setelah reduksi.