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Teknika: Jurnal Sains dan Teknologi
Published by Universitas Sultan Ageng Tirtayasa
ISSN : 1693024X     EISSN : 26544113     DOI : http://dx.doi.org/10.36055/tjst
Core Subject : Engineering,
Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Electrical & Electronics Engineering Engineering Industrial & Manufacturing Engineering
Teknika: Jurnal Sains dan Teknologi merupakan jurnal peer-reviewed dalam Bahasa Indonesia di bidang keteknikan, diantaranya bidang teknik sipil, bidang teknik mesin, bidang teknik industri, bidang teknik kimia, bidang teknik metalurgi, dan bidang teknik elektro.
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Articles 318 Documents
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Risk analysis of tender failure in the procurement of construction services Janita, Andreana; Dwi Hatmoko, Jati Utomo; Hermawan, Ferry
Jurnal Teknika Vol 19, No 1 (2023): Available Online in June 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i1.20059

Abstract

Failed tender often occurs in the process of procuring in government agencies. In BP2JK Central Java, the number of failed tender packages in the last 3 years is quite high, namely 10-35%. This study aims to analyze the risk of failed tender in the BP2JK area. The method used in this study is descriptive quantitative, where the analysis was based on historical procurement data in the last 4 (four) years and also on a questionnaire to 90 respondents consisting of 28 Pokja and 62 PPK in the BP2JK Central Java area. The results of the analysis show that there are 12 identified risks. If sorted from the highest risk level, these include: selection document errors, evaluation process errors, procurement implementation that was not on schedule, no participants passed the evaluation, bids did not meet requirements, procurement process errors, more than 1 (one) document uploaded, overqualified, owner estimate too low, participants did not show evidence, e-procurement system was hacked and price negotiations were not reached. While the method was frequently used as a risk response is reducing the possibility of a risk occurring, and followed by reducing the impact of risk, sharing risk, avoiding risk or accepting risk.  
Meningkatkan Availability Floating Hose SPM 165.000 DWT Menggunakan Inovasi Floating Hose Stabilizer untuk Menjaga Security of Supply BBM BBK Nasional Wicaksono, Aziz; Fridana, Hari; Nurjaya, Dalih Fajar; Priyambodho, Bambang Adhi
Jurnal Teknika Vol 19, No 1 (2023): Available Online in June 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i1.19223

Abstract

Single Point Mooring (SPM) 165,000 DWT (Deadweight Tonnage) is a facility at PT Kilang Pertamina Internasional RU VI Balongan that is used for unloading crude oil from tankers to storage tanks. This SPM is about 15 km from the jetty of PT KPI RU VI Balongan which is connected to two parallel 32 inch diameter submarine pipelines. The SPM is connected to 2 floating hoses of 16 inch diameter and 2 submarine hose strings using a turred system connected to 32 inch submarine pipelines through a PLEM. The PLEM is equipped with valves that can be controlled from the SPM using a control umbilical. The existing condition of the 165,000 DWT SPM was idle and unattended. During this period, two strings of floating hose tangled with each other and damaged the floating hose due to abrasion from overlapping. The occurrence of tangling on the floating hose at the same time and repetitive caused to lose and the 165,000 DWT SPM could not be operated and had an impact on the supply of crude oil to the PT KPI RU VI Balongan. In addition, floating hose leaks cause oil spills and pollute the surrounding aquatic environment and require large recovery costs to clean up the oil spills. This research aims to reduce the risk of tangling between 2 floating hoses by applying a floating hose stabilizer at several floating hose joints. The research method begins with a survey of existing floating hose conditions that experience tangling. Furthermore, analysis and modeling of the floating hose system is carried out. Then design and fabrication of floating hose stablizer for tangling prevention. And the results of the analysis and field conditions after the installation of the floating hose stabilizer are reduced potential tangling on 2 floating hoses thereby reducing the risk of losses both financial and environmental. 
The influence of treatment on cold work tool steel SKD 11 with temperature variations on mechanical properties Hasanah, Indah Uswatun; Priadi, Dedi; Dhaneswara, Donanta; Alhamidi, A. Ali
Jurnal Teknika Vol 19, No 1 (2023): Available Online in June 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i1.19422

Abstract

SKD 11 steel is a type of cold work tool steel that is popular and widely used in the manufacturing industry. SKD 11 steel is generally applied as dies, molds, cutting tools or others. Because of these applications. SKD 11 steel must have good wear resistance, hardness, dimensional stability, and toughness. So to improve the characteristics of the steel, a heat treatment process is carried out, but due to the high carbon content and alloying elements in the tool steel, the martensite finish (Mf) temperature of the steel becomes lower, so after the heat treatment process, usually the steel still leaves a lot of austenite phase. or commonly known as residual austenite. Residual austenite can affect the mechanical properties of SKD 11 steel, residual austenite can be removed by carrying out a cryogenic treatment process, this process is carried out after the quenching process. The heat treatment process this time was carried out using a vacuum furnace using an austenite temperature of 1040℃ and quenching using a medium in the form of nitrogen gas with a pressure of 3 bar. The cryogenic treatment process that was carried out afterward was carried out by varying the temperature of -80℃, -110℃, and -140℃. The test results obtained were then analyzed using an optical microscope and XRD (X-ray diffraction), as well as hardness testing and impact testing to determine the mechanical properties of the steel. Based on the research results it is known that the resulting microstructure contains martensite matrix and carbide M7C3 as primary carbide and M23C6 as secondary carbide, then by carrying out the cryogenic treatment process can reduce the percent of residual austenite, the lowest percent of residual austenite is obtained from the results of the cryogenic treatment at -140℃, which is equal to 1.15%. This is directly proportional to the hardness test results obtained, where the highest hardness value was also obtained by the sample with a value of 61.5 HRC, while the relationship with toughness is inversely proportional. The higher the hardness, the lower the resulting toughness. 
Metal recovering through recycling of printed circuit boards from computer devices using tabling and magnetic concentration methods Triana, Tiara; Oediyani, Soesaptri; Suwandana, Rahman Faiz; Pradana, Adjie; Syaifara, Zuhrainis; Kusumaningtyas, Dewi
Jurnal Teknika Vol 19, No 1 (2023): Available Online in June 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i1.17511

Abstract

The increasing human need for technology can have a negative impact on people's lifestyles which are becoming more consumptive. This causes the amount of electronic waste or e-waste to increase rapidly. Currently Printed Circuit Board is one of the wastes in e-waste which in 500 thousand tons of PCB contains around 150-200 thousand tons of metal. These metals are Cu, Pb, Zn, Au, Ag, Ni, Mn, Pd, and Fe. The metal contained in the PCB can be used as a secondary resource which can be further processed to produce valuable metals. The purpose of this research is to determine the particle size and prove whether the separation method is not effective in separating metals such as Cu and Ag from other metals. Based on XRF analysis to effectively separate Cu, Ag, and Au metals can use a particle size of 150μm with a Cu content of 78.673% and a particle size of 250μm with an Ag content of 0.083%. Separation is not effective to be carried out on PCB waste, this is because in the application of 1x magnetic separation, the Cu content is 80.51%. However, the type separation is less effective for the extraction of Ag metal. In separation using a shake table alone, the highest Ag content was obtained at 0.085% 
Electric mobility of Indonesia: a strategy for achieving net zero emission by 2050 Listijorini, Erny; Kanani, Nufus; Purwamargapratala, Yustinus; Satria, Dhimas; Sukamto, Dwinanto; Lusiani, Rina; Yusuf, Yusvardi; Jannah, Miftahul; Abdullah, Syarif; Pinem, Mekro Permana
Jurnal Teknika Vol 19, No 1 (2023): Available Online in June 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i1.19757

Abstract

Electric mobility mode could be a great opportunity to reduce emissions from the transportation sector. The future mobility calculator and electric car power demand, developed by Coalition for Urban Transitions and International Energy Agency, respectively, were used to analyze Indonesia’s shifting strategy toward electric mobility. It was shown that going to electric mobility will reduce 90% of Indonesia’s emissions from the transportation sector by the year 2050. Nevertheless, the charging infrastructure must be improved quickly to provide a proper ecosystem for electric mobility. Additionally, the electric vehicle waste management system is urgently needed soon. The success of shifting toward electric mobility not only benefits Indonesia’s environment but also strengthens its international credibility for sustainable development.             
Starch Nanoparticles for Food Packaging Applications: A Review Sri Agustina
Jurnal Teknika Vol 19, No 1 (2023): Available Online in June 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i1.21864

Abstract

Starch is one of the most used biodegradable polymers for food packaging applications. It has suitable properties and characteristic in the development of sustainable materials, including the biodegradability, non-toxicity, affordability, natural abundance, and renewability. The development of starch materials in form of nanoparticles has become more attractive due to its capability to functionalize with bioactive compound in forming of functional packaging materials. It also can be used as nanofillers to enhance the mechanical and barrier properties of biocomposite materials for food packaging materials. This article provides a short review of the development starch-based nanoparticles for food packaging applications. 
Superplasticizer and hydrated lime for high-strength concrete Kosim, Kosim; Fikri, Julian
Jurnal Teknika Vol 19, No 1 (2023): Available Online in June 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i1.16446

Abstract

According to SNI03-6468-2000, high-strength concrete is concrete with a minimum compressive strength of 41.4 MPa. The high strength concrete is useful in precast and prestressed concrete. This study aimed to find the effect of using superplasticizer and hydrated lime on the compressive strength of high-strength concrete K-500 when reviewed at the age of 3, 7, 14, and 28 days. This study used several percentages of superplasticizer for high-strength concrete mixtures, namely the proportions of 0%, 1%, 2%, and 3%. As for the hydrated lime that was tested, the percentages were 0%, 5%, 15% and 25%. The results of the compressive strength test of K-500 concrete without superplasticizer and hydrated lime at the age of 3, 7, 14 and 28 days respectively were 208 kg/cm2, 347 kg/cm2, 462 kg/cm2, and 525 kg/cm2. This results has met the requirements for compressive strength of K-500. Using of 1% to 3% superplasticizer with 5% of hydrated lime at the age of 28 days, the compressive strength obtained were 698.67 kg/cm2, 668.89 kg/cm2, and 465.48 kg/cm2. The compressive strength of using 1% to 3% of superplasticizer with 15% of hydrated lime at the age of 28 days were 508.89 kg/cm2, 473.33 kg/cm2, and 359.70 kg/cm2. As for the compressive strength of using 1% to 3% superplasticizer with 25% of hydrated lime at the age of 28 days were 320.00 kg/cm2, 300.44 kg/cm2, and 254.22 kg/cm2. From the test results, it can be concluded that the use of 1% admixture superplasticizer and 5% hydrated lime is the most optimal mixture compared to the others, with the compressive strength test result was 698.67 kg/cm2. In addition, the author also found that  the greater percentage of using the hydrated lime in the concrete mixture could reduce the compressive strength of the concrete. 
Analysis of the quality of the shredder plastic machine depend on variations in material plastic types and dimensions using the Taguchi Method Hendra Hendra; Nur Qodri Wijayanto; Sidik Susilo; Erny Listijorini; Hernadewita Hernadewita
Jurnal Teknika Vol 19, No 1 (2023): Available Online in June 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i1.21940

Abstract

The problem of plastic waste is critical things because everybody still often uses plastic for various daily needs. Therefore, recycling is considered very important to overcome these problems, including using a plastic chopping machine. The types of plastics used in this research are HDPE, PE, and PP plastics with experimental methods and the Taguchi method to determine the effect of plastic variations, the dimensions of the chopped results, and the percentage value of the contribution of the test variables to the plastic chopping machine. The results obtained in the study are that all types of plastics can be adequately chopped, with the optimum size for PP plastic being 6,8 x 4,5 mm with a processing time of 91,5 seconds. For PE, it is 16 x 10. 5 mm with a processing time of 170.6 seconds. While for HDPE, it is 68 x 34.5 mm with a processing time of 251.1 seconds. These results follow those obtained using the Taguchi method, with a contribution percentage of 77 % for the variable type of plastic followed by dimensions, weight, and thickness.   
Sentiment analysis on public opinion of electric vehicles usage in Indonesia using support vector machine algorithms Poedjimartojo, Naufal Avilandi; Pramesti, Dita; Fa’rifah, Riska Yanu
Jurnal Teknika Vol 19, No 2 (2023): AVAILABLE ONLINE IN NOVEMBER 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i2.21967

Abstract

Technological developments in the automotive industry have experienced significant progress in recent years. Currently, many electric vehicles are being produced as an environmentally friendly alternative to vehicles. The use of electric vehicles has become an intense topic of conversation in society, giving rise to various responses and opinions on Twitter. This research aims to analyze Indonesian people's sentiment regarding using electric vehicles through data collected from Twitter. Sentiment analysis is carried out using a machine-learning approach. The best method for pattern recognition problems is a Support Vector Machine (SVM) to sort each comment into positive or negative sentiments. Meanwhile, SVM classification performance was measured using the Confusion Matrix method. In this research, the Synthetic Minority Over-Sampling Technique (SMOTE) method and the Random Undersampling (RUS) method were used to overcome data imbalance. After the model creation and performance evaluation process, the best model produced was the baseline Support Vector Machine with a data sharing ratio of 70:30 without applying imbalance handling techniques. This model achieved an accuracy of 94.8%, a precision value of 95.5%, a recall value of 99.1%, and an F-1 Score value of 97.2%. 
Assesing compressive strength variations of galam wood in construction: A study of different sections and ratios Asnan, Muhammad Noor; Khoirulliyah, Ayu Arina; Noor, Rusandi; Vebrian, Vebrian
Jurnal Teknika Vol 19, No 2 (2023): AVAILABLE ONLINE IN NOVEMBER 2023
Publisher : Faculty of Engineering, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/tjst.v19i2.21934

Abstract

Due to of its inherent strength and durability, wood is a valuable and abundant natural resource that is frequently used in the construction industry, road infrastructure, and bridge architecture. Notably, Galam Wood stands out as a distinct possibility for construction applications, as it may be used in its natural state without the need for specialist treatments. The current research digs into an examination of several areas of Galam Wood, including the bottom, middle, and higher regions. This inquiry integrates distinct ratios (1, 2, 3, 4, and 5) to investigate their respective influences on the material's strength. The chosen diameter of the specimens, varying between 5 cm and 10 cm, emerges as a critical element impacting compressive strength. In the size conditions of 10 cm diameter specimens, differences in section reveal a minimal influence on compressive strength, contrasting significantly with the considerable effect reported in the 5 cm diameter test items. The observable dissimilarity in compressive strength readings for the 10 cm diameter specimens remains below the threshold of 10%. Nevertheless, the careful selection of diverse ratios distinctly modifies the compressive strength outputs, underlining the critical function of this parameter in the behavior of Galam Wood under compressive loads. 

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