IMPLEMENTASI TEKNOLOGI NANO MICROBUBBLE AERATOR PADA KOLAM LELE UNTUK MENINGKATKAN KADAR OKSIGEN AIR DAN MEMPERCEPAT PERTUMBUHAN BENIH IKAN LELE

Abstrak. Tujuan dari pengabdian masyarakat ini ialah untuk memberikan solusi terhadap permasalahan yang tengah dihadapi oleh mitra berupa teknologi tepat guna untuk meningkatkan kadar oksigen, kualitas air, dan mempercepat pertumbuhan benih ikan lele berbasis Nano MicroBubble Aerator yang dilengkapi dengan fitur, auto power timer, input oksigen, dan ozon generator. Perangkat ini dapat memproduksi gelembung-gelembung udara yang berukuran hingga 50 µm dan mengalirkan ke air kolam ikan. Metode pelaksanaan pengabdian masyarakat ini dimulai dengan observasi untuk mengetahui akar permasalahan pada mitra, implementasi perangkat teknologi, sosialisasi, dan pengujian terhadap pengaruh perangkat teknologi. Hasil pengujian menunjukan bahwa dengan parameter yang diajukan. Kadar DO pada air kolam meningkat sebanyak 25 persen, kapasitas benih ikan lele meningkat sebanyak 31 persen, dan jumlah benih ikan lele yang mati berkurang hingga 60 persen. Bedasarkan hasil pengujian tersebut dapat dismpulkan bahwa alat ini dapat menjadi solusi permasalahan yang dialami oleh mitra. Kata Kunci: Nano MicroBubble Aerator, Auto Power Timer, Ozon generator, Ikan Lele, Budidaya Ikan Tawar

PENGARUH KADAR DROMUS OIL DALAM MEDIA PENDINGIN TERHADAP KEKUATAN TARIK DAN STRUKTUR MIKRO BAJA ST 60 YANG MENGALAMI PROSES HARDENING TEMPERING

Baja St 60 adalah baja karbon sedang dengan 0,3-0,6% kadar karbon yang mempunyai kekuatan tarik 654 MPa. Proses hardening baja dilakukan untuk memperbaiki sifat mekanis baja yakni kekuatan yang dibutuhkan dalam dunia industri sebagai bahan pembuatan komponen otomotif dan pemesinan. Proses hardening yang dilakukan pada suhu 850 0C selama 40 menit dengan pendinginan cepat menggunakan variasi kadar dromus oil dalam media pendingin akan menghasilkan baja yang kekuatan tariknya tinggi tapi getas. Untuk mengurangi kegetasaan baja akibat proses hardening maka dilakukan tempering pada suhu 400 0C selama 60 menit didinginkan di udara. Tujuan dalam penelitian ini adalah; (1) mengetahui pengaruh kadar dromus oil 10%, 20%, dan 30% dalam media pendingin terhadap kekuatan tarik pada proses hardening tempering baja St 60; (2) mengetahui pengaruh kadar dromus oil 10%, 20%, dan 30% dalam media pendingin terhadap struktur mikro pada proses hardening tempering baja St 60. Data hasil uji tarik berupa nilai rerata ditampilkan dalam bentuk tabel dan histogram. Pengamatan struktur mikro menggunakan SEM dilakukan dengan membandingkan hasil foto struktur patahan baja St 60 sehingga dapat dianalisis mengenai struktur dan bentuk butiran masing-masing kelompok perlakuan. Hasil penelitian nilai rata-rata kekuatan tarik baja St 60 pada proses hardening tempering menggunakan kadar dromus oil 10% dalam media pendingin adalah 1560.986 MPa, dengan kadar dromus oil 20% adalah 1546.402 MPa dan dengan kadar dromus oil 30% adalah 1528.353 MPa. Hasil pengamatan struktur mikro SEM baja St 60 dengan kadar dromus oil 10% dalam media pendingin pada proses hardening tempering menunjukkan struktur patahan getas terdiri dari dominasi cleavage, spesimen menggunakan kadar dromus oil 20% menunjukkan struktur patahan ulet getas terdiri dari dominasi dimple tapi masih terlihat banyak cleavage dan spesimen menggunakan kadar dromus oil 30% menunjukkan struktur patahan ulet terdiri dari dominasi dimple. Pada penelitian ini, penemuan yang penting adalah bahwa baja St 60 dengan kadar dromus oil 20% dalam media pendingin pada proses hardening tempering memiliki kekuatan tarik yang tinggi dan perpatahan ulet. Hal ini dapat dijadikan sebagai pedoman produksi bagi praktisi ilmu logam dan dunia industri

IMPLEMENTASI EFISHERY SMART FEEDER SEBAGAI INOVASI PENGONTROL DAN PEMBERI PAKAN OTOMATIS

Budidaya ikan sudah dengan mudah kita jumpai diberbagai daerah karena kecendrungan masyarakat yang mengkonsumsi ikan, selain itu dalam budidaya ikan juga tidak memerlukan usaha yang ekstra namun harus dengan perhatian yang cukup. Seringkali budidaya ikan gagal dalam hasil panen karena beberapa kendala seperti biaya produksi yang terlalu tinggi yang dikarenakan overfeeding, hal ini juga akan membuat kualitas air menjadi jelek. Ibu Hunaebah juga mengalami hal serupa, karena pemberian pakan yang tidak terkontrol membuat hasil panen tidak menguntungkan. Tim PKM UM memperkenalkan eFishery Smart Feeder sebagai pengontrol dan pemberi pakan otomatis, tim mendatangi lokasi mitra untuk menyerahkan eFishery dan memberikan sosialisasi tentang penggunaan eFishery. Nantinya eFishery akan memberikan pakan secara otomatis sesuai waktu yang sudah ditentukan melalui aplikasi, penentuan ini sangat fleksibel mulai dari jumlah pakan hingga hingga frekuensi pemberian pakan. Data pemberian pakan juga akan tercatat dalam sistem dan dengan mudah dikontrol langsung oleh mitra melalui smartphone, adanya eFishery ini diharapkan akan membantu mitra untuk mengontrol pemberian pakan dan mendapatkan hasil panen yang maksimal

ANALISIS HASIL PENGECORAN LOGAM AL-SI MENGGUNAKAN LUMPUR LAPINDO SEBAGAI PENGIKAT PASIR CETAK

Penelitian ini bertujuan untuk menganalisa hasil pengecoran dengan membandingkan fluiditas dan kualitas coran. Selain itu juga bertujuan untuk mengetahui pengaruh lumpur lapindo terhadap kekerasan permukaan dan cacat coran pada logam paduan Al-Si. Metode penelitian yang digunakan dalam penelitian ini adalah metode kuantitatif. Metode penelitian yang digunakan ada-lah deskriptif dengan menggunakan jenis penelitian eksperimental. Subjek penelitian adalah lum-pur lapindo, bahan aluminium (Al-Si). Teknik analisis data deskriptif untuk mengetahui tingkat kekerasan, fluiditas, foto mikro dan makro untuk mengetahui cacat porositas dalam. Hasil pe-nelitian yang diperoleh, nilai fluiditas paling tinggi terdapat pada spesimen coran yang menggu-nakan campuran lumpur lapindo sebesar 7% yaitu 793,50 mm dari pola sebenarnya yaitu 200 mm. Sedangkan yang paling rendah terdapat pada spesimen coran yang menggunakan campuran lumpur lapindo sebesar 13% yaitu 748,80 mm dari pola sebenarnya yaitu 200 mm. Tingkat ke-kerasan tertinggi terdapat pada spesimen coran yang menggunakan campuran lumpur lapindo sebesar 15% dengan rata-rata nilai kekerasan 131,36 HV. Sedangkan yang paling rendah kekeras-annya terdapat pada spesimen campuran lumpur lapindo 7% dengan rata-rata nilai yaitu 118,16 HV. Dari hasil analisa cacat cor secara kasat mata menunjukkan bahwa spesimen coran yang me-nggunakan campuran lumpur lapindo sebesar 15% memiliki cacat cor yang paling sedikit dan pa-ling kecil bila dibandingkan dengan spesimen lainnya. Dari hasil penelitian ini dapat ditarik kesim-pulan bahwa lumpur lapindo dapat menjadi kandidat terbaik pengganti bahan pengikat bentonit pada pengecoran pasir (sand casting) karena memiliki kecekatan yang baik untuk bahan pengikat

Critical Solid Fraction Point Analysis: Case Study on Cement Mill Machine Diaphragm

During the solidification process, metal liquids turn into solid geometry units including the riser and gating system. The disruption in the liquid flow often causes shrinkage in the object. Critical Solid Fraction Point is a critical point where the continuous liquid supply turned solid and unable to pour to some sections. Simulation software can predict the critical solid fraction time of an object and the liquid supply behavior. The simulation helps the designer in the casting design. The application of low steel alloys in the cement industry, e.g., the Diaphragm, needs development to minimize the shrinkage. This research aimed to analyze the critical solid fraction point in the diaphragm steel casting products. The primary objective of this research was to predict the critical solid fraction point during solidification, started from the longest time in the riser/feeder using SOLIDCast 8.1.1 casting software and provided improvement recommendation to minimize the shrinkage

Optimum Conditions for EOR Using Nanofluids Subjected to EM Waves

Today‟s major challenge for oil industry is to improve the oil recovery from the reservoir. Various enhanced oil recovery (EOR) methods have been applied in the field and the steam injection is one of the most favourable methods. The deep reservoir will result in failure of this method due to excessive heat dissipation. In this situation, generating and injecting steam may be uneconomical due to the tremendous reduction of the recovery. Some methods using nanotechnology have been introduced and elaborated. However, we propose the electromagnetic (EM) method as an alternative due to its long range transmission of the transverse waves. These EM waves, coupled with some nanoparticles (NP), can modify the surface energy. We propose an optimum conditions based on some parameters namely, frequency, flux density, space charge density and skin depth, employing Maxwell and Helmholtz equations which interact with some magnetic and dielectric nanoparticles. A newly-designed EM antenna with a very high flux density is the model for this specific purpose. The electrical energy from the antenna transfers the waves to the dielectric and resistive nanoparticles, which is then transferred to the fluid with high capillary force. This results in lower surface tension which reduces the oil viscosity. In order to investigate the transport phenomena of the nanoparticles in porous medium, we applied Darcy‟s law. Our preliminary study for scale model simulations showed that at a frequency of 0.125Hz, the electric field of the curve antenna with magnetic feeders was 4280% higher compared to the one without magnetic feeders,At a frequency of 0.125Hz, the magnetic field of the curve antenna with magnetic feeders was 3677% higher in comparison with the one without magnetic feeders. With the increasing frequency from 0.125Hz to 9Hz, the electric field and magnetic field of the antenna with feeders decreased by 99%. The permeability and porosity of glass beads packed column was 30.58mD and 25.87% respectively. It was observed that the cumulative recovery of oil reached 21.11% by using ZnO nanofluid with electromagnetic waves, 17.23% by using ZnO nanofluid without electromagnetic waves, 32.59% by using iron oxide nanofluid with electromagnetic waves, and 29.68% by using iron oxide nanofluid without electromagnetic waves. In summary, the use of ZnO and iron oxide nanoparticles as nanofluids with electromagnetic waves is considered the most effective to use in enhanced oil recovery

PENGARUH FAKTOR DEMOGRAFI DAN FAKTOR PSIKOLOGIS TERHADAP PENGAMBILAN KEPUTUSAN INVESTASI PADA REKSADANA

Many factors may affect investors in making investment decision, some of which are demographic factors (gender, age, marital status, education level, family member, occupation, income) and psychological factors (overconfidence, data mining, social interaction, emotion, representativeness, familiarity, considering the past). Those factors thought to have an influence on investment decision making, one of them is mutual funds. The purpose of this study was to examine the influence of demographic factors and psychological factors on mutual fund investment decision. The research object of this study are investors who invest in mutual fund in Surabaya. Methods of data collection in this study used questionnaires by purposive sampling of 75 mutual fund investors in Surabaya. To answer the problem and test the hypothesis proposed in this study, the researcher used descriptive analysis and inferential analysis (statistical tests) by using chi-square and log linear. The expected result from this study is demographic factors and psychological factors have a significant influence on mutual fund investment decision. Key words : Demographic Factors, Psychological Factors, Mutual Fun

Utilization Of Carbon Nanotubes In Electromagnetic Wave Detectors

Direct detection of hydrocarbon by an active source using electromagnetic (EM) energy termed seabed logging (SBL) has shown very promising results. However, currently available electromagnetic wave technology has a number of challenges include sensitivity and frequency matching. This paper presents development of the carbon nanotubes (CNTs) as electromagnetic wave detector due to outstanding properties of carbon nanotubes. They are currently one of the desired materials for advanced technologies. Two types of detectors were developed in this work, carbon nanotube-based (D1) and without nanotube-based (D2) detectors. Various configuration and arrangement for each type of detector were investigated to determine the one with the highest detection measurement and stability of frequency stability of detection system. It was found that 20 turn-coils coil placed at its centre gives the maximum detection of induction voltage, 39.61 mV. However, the 20 turn- coils with CNTs which gives 36.50 mV is the preferred EM detectors due to the stability in frequency of the detection system

Effect of Heating Temperature, Holding Time and Stabilization Temperature on the Al-Foam Properties

The interest in metallic foam is increasing since their cellular structures have a unique combination of properties such as high stiffness, low density, lightweight, high specific strength, and thermal insulation. Commonly, the performance of metallic foam can be improved by the heat treatment process. However, the previous heat treatment methods still present the brittle crack path and the research on heat treatments of the metal foam properties is very limited. In this study, individual parameters in stress relieving treatment that contribute to Al-Foam properties were investigated. The stress-relieving process of the samples was performed using a vacuum furnace. The composition of aluminium foam was determined by X-Ray Fluorescence (XRF). The hardness test was conducted using a microhardness tester. Quasi-static compression test was conducted by a universal testing machine. From the SEM-EDX elemental images, it can be observed that traces of Ca, Fe, Ti, and Si have a homogeneous distribution in the Al-matrix. In the result obtained, the mechanical properties of aluminium alloy foam decrease when the heating temperature is enhanced. The mechanical properties of closed-cell aluminium alloy increase with the reduction of the holding temperature. This was due to the recovery and recrystallization process which depended on time and temperature during the heat treatment process. The mechanical properties of aluminium foam were raised after increasing the stabilization temperature. This finding was due to the vibrational atomic motion in the recovery process

The Effect of Rotational Speed, Friction Duration, and Pressure on Tensile Strength of AISI 6061 Welding Joints

Electric arc welding with covered electrodes is ideally suited for flat plates. If this technique is employed for welding rigid bodies, the results would be of poor quality. One viable solution to weld rigid bodies is through friction welding. The study aimed to investigate the tensile strength of specimens subjected to friction welding with variations in rotational speed, friction time, and pressure and to examine the microstructure of friction welding joints. This research used the one-shot case study design and involved descriptive analysis. The descriptive analysis described the results of tensile testing and microstructure of welding joints. Results showed that the specimen subjected to a 2850 rpm rotational speed, 60-second friction duration, and 8 MPa pressure had the highest tensile strength of 15.19 Kgf, whereas that rotated at 2850 rpm under 8 MPa pressure for 80 seconds had the lowest tensile strength, i.e. 12.25 Kgf. The photomicrographs showed that the friction welding joints underwent no phase change, but the refinement of Mg2Si particles occurred in the Zpd and Zpl zones. Also, the Zud zone consisted of the same form of Mg2Si particles as the untreated specimen