cover
Contact Name
Wara Dyah Pita Renga
Contact Email
wdpitar@mail.unnes.ac.id
Phone
-
Journal Mail Official
wdpitar@mail.unnes.ac.id
Editorial Address
Sekaran Gunungpati, Semarang, Central Java
Location
Kota semarang,
Jawa tengah
INDONESIA
Rekayasa: Jurnal Penerapan Teknologi dan Pembelajaran
ISSN : 02165631     EISSN : 25276964     DOI : https://doi.org/10.15294/rekayasa
Core Subject : Engineering,
REKAYASA journal publishes exciting articles from all fields of research and Engineering Science. The journals primary focus is on research practice and engineering processes utilizing biomass or factory waste. The engineering journal is an open-access peer-reviewed journal that publishes articles from all areas of Engineering and Science research.
Articles 5 Documents
Search results for , issue "Vol 19, No 2 (2021): December 2021" : 5 Documents clear
Recovery in Oil Contaminated Soil (A108D) by Using Subcritical Water
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 19, No 2 (2021): December 2021
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v19i2.34429

Abstract

Production activities in the oil and gas industry potentially cause environmental pollution, one of which is soil pollution. Soil contamination is generally found in oil refinery areas due to pipe spills or leaks, spills during tank cleaning or loading-unloading, and oil transportation processes. In this study, the treatment of oil-contaminated soil waste was carried out through oil recovery contained in the soil using water. The treatment process was applied to 3 types of soil waste, that is soil contaminated with oil, sandy soil contaminated with oil, and sludge, with processing times of 30, 60, 90, and 120 minutes, and flow rates of 46, 90, 139, and 183 mL/minute. The water temperature used for processing is ±175 oC with a pressure of 14.5 atm. The results showed that the average decrease in oil content in the samples of oil-contaminated soil, oil-contaminated sandy soil, and sludge, respectively, was 37.7%; 5.8%; and 88.4%. Therefore, the application of this method is most effectively applied to sludge-contaminated soil waste. Based on variations in flow rate and processing time, the longer the processing time, the less oil content in the oil-contaminated soil waste, and the more recovered oil produced. Through the application of the oil recovery system on this oil-contaminated soil waste, the company can save budget, especially the budget for waste treatment reaching Rp 1,142,808.33 per ton. However, some parameters in the liquid waste from this treatment process are above the environmental quality standard so that it needs to be managed further.
Synthesis of Crude Palm Oil-Based Polyol Ester as Biolubricant
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 19, No 2 (2021): December 2021
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v19i2.36292

Abstract

The decline in crude oil reserves as a raw material for the manufacture of lubricants and the need to reduce pollution from mineral lubricants has begun to encourage the use of waste and pollution reduction technologies to reduce environmental problems. One realization is an alternative lubricant called biolubricant. Biolubricant is considered rapidly biodegradable, non-toxic, and thought to pose less or no risk to the environment and its users compared to petroleum-based lubricants. This study aimed to produce polyol esters as biolubricant through the acetylation reaction of polyols from crude palm oil (CPO) and to investigate the physical and chemical properties of the resulting polyol esters. From the study results, the kinematic viscosity of 40 °C in the resulting polyol ester was 46.2339 cSt, while the kinematic viscosity at 100 °C was 8.7417 cSt. The viscosity index and flash point of polyol ester obtained were 144.0818 and 282.3 °C. The highest conversion of 38.41% polyol ester production was achieved at 80 °C for 35 minutes using a 3% wt/wt catalyst. This study shows that palm oil esters have great potential to obtain lubricants with high biodegradability and better physicochemical properties.
Development of E-Module for Construction Management Application Course Based on Building Information Modeling
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 19, No 2 (2021): December 2021
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v19i2.35152

Abstract

The rapid demands of technological development in the construction world require competent and skilled human resources to operate BIM-based software. One of the university's efforts to address this is by adopting Building Information Modeling in one of the lecture teaching materials, one of which is the Construction Management Application Course. The research and development aim to produce e-modules Building Information Modeling-Based Construction Management Application Course at the Building Engineering Education Study Program, Universitas Negeri Jakarta. The method used in this study is the Research and Development by using a 4D model. The 4D model consists of 4 systematic stages: define, design, development and Dissemination. Based on the validation results, the developed e-modules fall into the very feasible category with 82% of material experts and 93% of media experts. Limited trial results and Dissemination of N-gain values of 0.65 (moderate) and 0.75 (high) show learners' cognitive improvement. Along with the respondents' questionnaire results, the percentage of practicality was 90.2%, which falls into the Very Practical category. Based on the advantages processed, the Construction Management Application e-module regarding the procedures of making 4D and 5D simulations in 2-story house buildings using Autodesk Navisworks software is suitable as advanced teaching materials in the Construction Management Application course.
Bio Coating Based on Damar Resin on Mild Steel in Corosive Media (Acid Effect) by Using Silica from Rice Husk Extract
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 19, No 2 (2021): December 2021
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v19i2.37600

Abstract

Bio coating is a natural anti-corrosion material that can be easily degraded and renewed. Rice husk extract and damar resin are alternative natural materials that are believed to have a relatively high silica content, so they can be used as a substitute for synthetic chemicals to protect metals from corrosion. This research was conducted to determine the bio-coating ability of mild steel in H2SO4 corrosive media. The object of the experiment used rice husk waste and damar resin as the primary raw materials. The analytical method used is the weight loss method. The resin sap and silica sol obtained from the ashing of rice husks are mixed to form a homogeneous product. Metal samples coated with bio-coating material are immersed in 0.5 M sulfuric acid solution, with variations in silica concentrations of 500, 1000, 1500 ppm, 1, 2, and 3 hours, and at temperatures of 40, 60, and 80°C, which is then tested for the ability of the bio coating material. The results show that the higher the temperature and the longer the immersion time, the corrosion rate on the metal increases. The variation of the 1500 ppm silica concentration shows better efficiency results than other concentrations at a temperature of 40°C for an immersion time of 1 hour.
Implementation of Solar Panels as an Energy Source for Automatic Fish Feed Machine Control Systems
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 19, No 2 (2021): December 2021
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v19i2.41019

Abstract

Feed is the main need for fish consumption, feeding is sometimes a problem for breeders. An automatic fish feed machine with Arduino control via an android phone's Bluetooth signal as the communication method, equipped with an alarm indicating the condition of the feed is running out is the best solution. The automatic feed machine is placed in a pond outside the house so that solar energy can be absorbed by solar panels as a source of electrical energy for the machine and battery charger. Backup power when it's cloudy or at night and the machine doesn't need a state electricity company power source. The implementation of a 2.5 Wp solar panel and a 3000 mAh battery in this automatic fish feed machine is needed to simplify the daily feeding process. The result of this research is the maximum distance of control via an Android phone is 60 meters without obstructions and 30 meters with obstacles. When the battery voltage is 8 volts, the solar charger controller automatically cuts off the supply to the load to avoid a battery voltage drop. When the battery voltage rises to 10 volts, the load is activated again. From full 12.2-volt battery voltage to 8-volt drop it takes 6 hours and the load is automatically disconnected, 1.5 hours is needed for the battery to be re-charged by solar panels when the weather conditions are sunny and the load is active again.

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