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Rekayasa: Jurnal Penerapan Teknologi dan Pembelajaran
Published by Universitas Negeri Semarang
ISSN : 02165631     EISSN : 25276964     DOI : https://doi.org/10.15294/rekayasa
Core Subject : Engineering,
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.
Arjuna Subject : Teknik (semua kategori) - Teknik (Lain-Lain)
Articles 319 Documents
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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.
Addition Rice Husk on the Density and Impact Strength of Non-Asbestos Brake Pad Composites Prepared by The Hand Layup Method Fitriyana, Deni Fajar; Widodo, Rahmat Doni; Kriswanto, Kriswanto; Athoillah, Ahmad; Prasetyo, Ares Yudi; Alrasyid, Mochamad Dzaki
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 20, No 1 (2022): July 2022
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v20i1.45636

Abstract

In train operation, brakes are an essential component because they involve the safety of passengers. Therefore, brake pads must be replaced periodically according to their lifespan. Currently, the most widely used train brake pad material is composite. Unfortunately, most train brake pads in Indonesia still use imported products because no industry can produce train brake pads of the desired quality. This study aims to manufacture and characterize composite materials for friction material for train brake pads that meet quality standards to substitute imported products. It needs to reduce dependence on imported products while at the same time encouraging the strengthening of the structure of the domestic manufacturing industry. In addition, agricultural waste in rice husks will be used to produce more environmentally friendly products. In this study, the composition of the types of composite materials, which include binder, reinforcement, abrasive, and filler materials, will be examined. Making composite materials in this study will use the hand layup method. Material characterization carried out includes impact testing and density. The characterization results show that using rice husk as a filler greatly influences the density of the resulting composite material. Specimen 5, made from epoxy, rice husk, iron filings, and Al2O3 (wt.%) at 50%, 20%, 15%, and 15%, respectively, was able to produce a higher density compared to the composite without rice husk and epoxy material. The results of this density test support the results of the impact tests that have been carried out. The higher the rice husk content, the higher the density produced. Adding rice husk can increase the mechanical properties of the resulting composite material.
Manufacture Bioplastic Composite made of Corn Starter and Poly Vinyl Alcohol with the Addition of Beeswax Ramadhan, Aditya Prian; Purnavita, Sari; Rahayu, Lucia Hermawati
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 20, No 1 (2022): July 2022
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v20i1.37275

Abstract

Bioplastics are environmentally friendly plastics that naturally can be easily degraded. One of the natural ingredients that can be used is corn starch. This study aims to study the effect of heating temperature and the addition of beeswax on the characteristics of bioplastics. This study used two independent variables. This study used the heating temperature of the material at 60-80 °C and the addition of beeswax up to 2% of the total weight. The amount of poly vinyl alcohol and corn starch was dissolved in water and further to the plasticizer in glycerol with heating time. The characteristics to be obtained are the properties of bioplastics that have been synthesized against water resistance, tensile strength, and elongation tests. The lowest heating temperature of 60 °C had a minor water absorption of 42.85%. At a heating temperature of 65 °C, it gives the highest tensile strength and elongation, respectively, 5.15 Mpa and 29.39%. The addition of beeswax affects water resistance, tensile strength, elongation, and biodegradation values. Water resistance will be higher with the addition of beeswax. In addition to 2 g of beeswax, bioplastics have the highest tensile strength value, and elongation was obtained, respectively, 9.55 Mpa and 31.54%.
Production of Persimmon Juice with Technology Ultrafiltration of Membrane to Improve People's Skills Rengga, Wara Dyah Pita; Siami, Desy Hikmatul; Nabil, Nisrina Hasna'; Handoko, Pratama Senapati Bagus; Pangestu, Indra Sakti; Saputra, Danang Dwi; Hidayah, Fauziyah Nurul
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 20, No 1 (2022): July 2022
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v20i1.44764

Abstract

COVID-19 impacted the Grabag Village community's economic instability, resulting in the termination of employment. Grabag Village has the potential for persimmons as fresh fruit consumption, which lasts only less than two weeks. It is the background for the community empowerment activities for three months. The program aims to utilize membrane ultrafiltration technology and introduce the use of chitosan preservatives to the community. The implementation method applied includes the preparation, implementation, and evaluation stages. The results of this activity program show an increase in the knowledge of the partner community regarding the basic introduction of persimmon fruit, diversification of persimmon fruit products, and understanding of the production process with an average value of above 80%. However, only 75% of all partners understand online marketing from a technological point of view. Community assistance is needed to face the challenges of digitizing business actors to expand market share and reach increasingly widespread smartphone users. The community knows the potential of persimmon fruit, which can be used to make many processed products into ready-to-drink drinks. The partner also knows chitosan as a natural preservative and practices adding it directly to fruit juice, packaging, and labelling. After the socialization stage, the community is more educated regarding the procedures for making ready-to-sell persimmon juice from persimmon fruit.
Analysis of Solar Power Generation System Requirements based on Economic Factors in Photovoltaic Specification Selection Septian MN, Angga; Nurdiyansah, Reza; Setiawan, Agus; Sunardi, Sunardi
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 20, No 1 (2022): July 2022
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v20i1.45841

Abstract

A solar power generation system is a significant investment, and its economic viability is crucial. Analyzing economic factors helps ensure that the selected photovoltaic specifications are cost-efficient, the financial investment is justified, and the energy needs, the project remains sustainable in the long term. It assists stakeholders in making decisions based on economic considerations, energy production and environmental impact. This research aims to analyze the requirements for solar power generation and the selection of photovoltaics based on economic factors. The results of this research explain photovoltaic specifications in terms of efficiency, capacity, technology, and characteristics to understand how they affect the requirements of solar power generation systems. Based on economic factors such as initial investment costs, operational costs, and long-term economic benefits generated. The simulation of the photovoltaic system indicated that photovoltaics with a capacity of 485Wp, using monocrystalline type Canadian Solar HiKu5 Mono PERC, produce the highest output value of 8 kWp using 15 solar panels. It indicates that these specifications offer a high potential for electricity production. The highest economic value amounts to IDR 71,874,000 with an annual yield of 2,920 kWp. The use of monocrystalline photovoltaics is superior and more durable compared to polycrystalline. However, monocrystalline types tend to be more expensive in terms of price. Nevertheless, investment in types can provide long-term benefits in terms of efficiency, durability, and higher electricity production potential despite the higher initial costs. The selection of photovoltaic types should consider these factors, including available budget, desired efficiency, and overall system requirements.
The Implementation of the Use of Seed Bag Panel Boards for Vegetable and Crop Farmers in Kopeng Prajanti, Sucihatiningsh Dian Wisika; Bintari, Siti Harnina; Nugrahani, Rahina
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 20, No 1 (2022): July 2022
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v20i1.47538

Abstract

One of the agricultural problems in the spotlight is the quality of harvest and postharvest commodities, which still needs to improve due to the failure of special handling. One solution for handling perishable and low-value agricultural commodities is to sell agricultural products alive and in special packaging on panel boards as wall decorations based on green interiors with an urban farming concept. The research aims to implement the concept of vegetable and flower panel boards based on green interiors to increase the marketing value of agricultural products in Kopeng. The application of this panel board concept is to improve the quality of agricultural products because they are easily damaged, so the public consumes fresh vegetables of good quality with this panel board. Three simultaneous benefits of panel boards are art, aesthetics and product freshness when consumed. The prototyping is panel board products with steps to ensure the concept's design, functionality and feasibility, panel size, layout of vegetables and flowers, panel placement and other supporting structures. Test the prototype by growing vegetables and flowers and storing fruit from user input. Prototypes that are refined and tested well are then developed into marketing strategies. This program is about applying the panel board concept to improve the quality of agricultural products by providing added value to agricultural products so that they can increase the profits received by farmers. From the implementation that has been carried out, marketing results have increased by 10% from marketing before using seed bags.

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