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Ani Tjitra Handayani
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INDONESIA
KURVATEK
ISSN : -     EISSN : 24777870     DOI : https://doi.org/10.33579/krvtk.v4i1
Jurnal KURVATEK diterbitkan pertama kali tahun 2016 oleh Pusat Penelitian dan Pengabdian masyarakat pada Sekolah Tinggi Teknologi Nasional Yogyakarta. Jurnal ini mempunyai misi sebagai media pengembangan ilmu pengetahuan dan teknologi dalam bidang geologi, pertambangan, elektro, sipil, material teknik,konversi energi, enegi terbarukan, serta perencanaan wilayah dan kota. Area tulisan dalam jurnal ini cukup luas. Cakupan penulisan mulai dari kajian pustaka maupun ekperimen yang ditulis dengan kaidah-kaidah penulisan ilmiah yang baik dan benar.
Articles 265 Documents
KUAT TEKAN BETON ROLLER COMPACTED CONCRETE (RCC)-FLY ASH 15% YANG DIRENDAM SODIUM SULFAT Jodiansyah; Sulistyorini, Dewi; Gutama, Detha Sekar Langit Wahyu
KURVATEK Vol 9 No 2 (2024): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v9i2.5362

Abstract

RCC (Roller Compacted Concrete) pavement is known for its durability, cost-effectiveness, long lifespan, and low maintenance. In this study, RCC concrete was compacted using a vibrator hammer in three layers, each with a compaction time of 20 seconds per layer. The mix proportions were based on SNI 03-2834-2000 and modifications from several journals, with a target compressive strength of 25 MPa. The materials used included coarse aggregate, fine aggregate, Portland Composite Cement (PCC), water, fly ash, and superplasticizer (SPC). The percentage of fly ash used in this study was 15% of the cement weight, with a total of 12 test specimens. The compressive strength of cylindrical concrete samples with a diameter of 15 cm and a height of 30 cm was tested using two immersion variations: ordinary water and sodium sulfate (Na2SO4), and two durations: 14 days and 28 days. The results showed that the compressive strength of RCC 15 B-14 was 49.16 MPa, RCC 15 B-28 was 52.29 MPa, RCC 15 S-14 was 46.87 MPa, and RCC 15 S-28 was 50.65 MPa. Immersion in sodium sulfate for 14 days resulted in a compressive strength reduction of 4.7% compared to ordinary water immersion, while immersion in sodium sulfate for 28 days resulted in a compressive strength reduction of 3.1% compared to ordinary water immersion. However, the compressive strength results still exceeded the planned strength of 25 MPa
EVALUASI PENGGUNAAN PREFABRICATED VERTICAL DRAIN (PVD) PADA TANAH YANG MEMILIKI KARAKTERISTIK LUNAK Darmawan, Angga; Sutrisno, Widarto; Faylani, Leo
KURVATEK Vol 9 No 2 (2024): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v9i2.5363

Abstract

Penurunan tanah yang terjadi pada suatu area konstruksi merupakan tantangan yang harus diselesaikan dalam perencanaan sebelum dilakukan suatu konstruksi. Setiap jenis tanah memiliki karakteristik yang berbeda sehingga penanganannya juga harus disesuaikan. Pada lokasi yang dilakukan penelitian, jenis tanah yang ada adalah tanah lunak dengan material pembangunnya yang sudah tidak baik untuk dijadikan area konstruksi karena terjadi amblasan. Penggunaan Prefabricated Vertical Drain (PVD) pada tanah lunak telah menjadi solusi yang efektif dalam mempercepat proses konsolidasi tanah dan mengurangi risiko penurunan yang berlebihan. Penelitian ini bertujuan untuk mengevaluasi efektivitas penggunaan PVD pada tanah lunak melalui analisis data lapangan yang diperoleh dari suatu kegiatan konstruksi. Metodologi penelitian melibatkan studi kasus di area dengan kondisi tanah lunak, pemasangan PVD dengan pola tertentu, serta pengukuran penurunan tanah sebelum dan sesudah pemasangan PVD. Akan tetapi, hasil penelitian menunjukkan bahwa pada tahap sebelumnya yang telah dilakukan pemasangan PVD dan penimbunan tahap 1, penurunan tanah yang terjadi belum secara signifikan teratasi. Dengan penurunan tanah yang masih bisa diizinkan maksimal 1,85 meter, pada area tersebut masih mengalami penurunan tanah hingga 1,75 meter. Selanjutnya, dilakukan penimbunan tahap 2 namun penurunan tanah yang terjadi belum teratasi serta penurunan yang terjadi semakin dalam, yaitu sebesar 4,35 meter. Hal ini mungkin disebabkan oleh terjadinya kerusakan platform konstruksi dan PVD akibat amblasan yang terjadi terlalu dalam, dengan keseluruhan mencapai 6,064 meter setelah dilakukan pemadatan (preloading) hingga 3 tahap. Dengan demikian, penggunaan PVD bukan berarti tidak menjadi solusi namun terjadinya faktor lain seperti kondisi tanah yang sudah terlalu cacat.
STABILISASI TANAH EKSPANSIF DI KECAMATAN LUMBIR, KABUPATEN BANYUMAS, JAWA TENGAH Budianta, Wawan
KURVATEK Vol 9 No 2 (2024): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v9i2.5365

Abstract

Tanah ekspansif dijumpai di beberapa lokasi di Kecamatan Lumbir, Kabupaten Banyumas, Provinsi Jawa Tengah. Keberadaan tanah ekspansif ini mempunyai implikasi terhadap banyaknya kerusakan jalan di lokasi tersebut yang dikarenakan oleh sifat mudah mengembang yang dimiliki oleh tanah ekspansif. Penelitian ini bertujuan untuk melakukan stabilisasi tanah ekspansif di lokasi penelitian dalam skala laboratorium. Tiga sampel tanah diambil di lokasi penelitian dan dilakukan analisis ukuran butir, kandungan mineralogi dan indeks plastisitas. Percobaan laboratorium penambahan kapur dilakukan pada tiga perlakuan yaitu 2,5%, 5%, dan 7,5%. Hasil analisis distribusi ukuran butir, menunjukkan bahwa persentase ukuran butir lempung yang rendah dan didominasi oleh ukuran butir lanau dan termasuk ke dalam golongan loam dan silt loam serta menunjukkan ketiga sampel memiliki gradasi yang cukup buruk. Hasil plotting nilai batas atterberg pada grafik plastisitas, sampel termasuk ke dalam kelompok CH (lempung plastisitas tinggi) dan CL (lempung plastisitas rendah). Analisis mineralogi menunjukkan bahwa sampel tanah tersusun atas mineral kaolinit dan monmorilonit. Kemudian, percobaan dengan melakukan penambahan kapur pada tanah ekspansif dapat menurunkan nilai indeks plastisitas. Penurunan terbesar terjadi pada sampel dengan penambahan kapur 7,5% yang memiliki nilai penurunan indeks plastisitas sebesar 51,23%.
METODE PERKUATAN LERENG DI INDONESIA: SYSTEMATIC LITERATURE REVIEW Mahfuzh, Andika Syahal; Surjandari, Niken Silmi
KURVATEK Vol 9 No 2 (2024): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v9i2.5366

Abstract

Lereng adalah permukaan tanah yang membentuk sudut tertentu terhadap bidang horisontal dan tidak terlindungi. Lereng membutuhkan perkuatan untuk mencegah kegagalan atau kelongsoran yang disebabkan oleh faktor manusia atau faktor kondisi alam. Perkuatan lereng berfungsi menjaga stabilitas dan meningkatkan faktor aman (safety factor) pada suatu lereng. Tujuan penelitian ini adalah mengetahui perkuatan lereng yang paling banyak digunakan di Indonesia. Metode yang digunakan yaitu Systematic Literature Review (SLR) dengan mengumpulkan 100 jurnal melalui Sinta, Scopus, dan Garuda, lalu dipilih berdasarkan tahapan yang sudah ditentukan yaitu Research Question, Search Proses, Inclusion and Exclusion Criteria, dan Quality Assesment. Hasil Penelitian menunjukan pada RQ1 perkuatan lereng yang paling banyak digunakan di Indonesia yaitu Dinding Penahan Tanah dengan persentase 29,87%, Soil Nailing 20,78%, Geosintetik 19,48%, Pile 16,88%, Tumbuhan/Vegetasi 5,19%, Counterweight 3,9%, Subdrain 2,6%, dan Model Scale Test With X-Block 1,3%. Lalu, pada RQ2 menunjukan alasan penggunaan Dinding Penahan Tanah karena topografi Indonesia yang berbukit dan berlereng dengan derajat yang cukup besar atau curam, sehingga membuat lereng rentan terhadap erosi dan longsor. Pada RQ3 disampaikan implementasi perkuatan Dinding Penahan Tanah untuk solusi permasalahan lereng di Indonesia. Berdasarkan hasil systematic literatur review, dinding penahan tanah cocok dipakai di Indonesia dikarenakan dalam pembuatannya menggunakan material-material yang mudah didapat. Jadi, dalam perkuatan lereng di Indonesia direkomendasikan perkuatan menggunakan Dinding Penahan Tanah.
EVALUATION OF THE IMPACT OF CAPACITOR BANK CAPACITY ON ENERGY EFFICIENCY AND POWER FACTOR AT ASTON INN HOTEL TASIKMALAYA Faridah, Linda; Rivaldi Vadilah; Usrah, Ifkar
KURVATEK Vol 9 No 2 (2024): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v9i2.5375

Abstract

This study aims to evaluate the impact of capacitor bank capacity on energy efficiency and power factor at Aston Inn Hotel Tasikmalaya. The hotel's electrical system is characterized by a predominance of inductive loads, which generate a considerable amount of reactive power, thereby decreasing the overall power factor. To address this issue, capacitor banks are commonly used as a power factor correction tool, helping to reduce reactive power, minimize energy losses, and lower operational costs. However, the correct sizing of capacitor banks is crucial, as incorrect capacities can lead to system inefficiencies and potential instability. In systems where the power factor is low, there is an increase in electrical current, which contributes to higher energy losses in the form of heat and, consequently, elevated operational expenses. This study adopts a comprehensive approach involving direct measurement of the hotel's electrical system, detailed analysis of load data, and calculation of the ideal capacitor bank capacity required for optimal performance. The aim is not only to improve energy efficiency but also to enhance the overall stability and safety of the hotel's electrical network. The results of this research reveal that the currently installed capacitor bank has a capacity of 300 kVAr, which is significantly larger than the ideal requirement of 55 kVAr as determined through load analysis. This substantial excess in capacity results in a power factor shift from lagging to leading. Such a shift can lead to adverse effects on the electrical system, including potential instability, equipment malfunction, and increased wear and tear on system components. Additionally, it was discovered that the existing Power Factor Controller (PFC) is not operating at its optimal setting, further complicating the situation and preventing the system from achieving the desired power factor improvements. Based on these findings, it is recommended that adjustments be made to the capacitor bank capacity to align with the calculated ideal value. Moreover, a reconfiguration and proper tuning of the Power Factor Controller are necessary to ensure optimal performance. These corrective actions are expected to enhance power factor correction, improve energy efficiency, reduce operational costs, and maintain system stability within the hotel's electrical network.
ANALYSIS OF LIQUEFACTION POTENT ANALYSIS OF LIQUEFACTION POTENTIAL USING THE ANALYTICAL HIERARCHY PROCESS METHOD IN BANTUL DISTRICT, YOGYAKARTA PROVINCE, INDONESIA: ANALYSIS OF LIQUEFACTION POTENTIAL Nurhaci, Dian Susri
KURVATEK Vol 9 No 2 (2024): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v9i2.5409

Abstract

Abstract — The earthquake that struck the Bantul district of Yogyakarta on May 27, 2006, with a Richter scale value of 6.3, caused sandboils in various areas in Bantul Regency. These symptoms are referred to as liquefaction events, and the phenomenon is fascinating to research. These symptoms are referred to as liquefaction events, and the phenomenon is intriguing to researchers. Liquefaction in Bantul Regency is induced by the area's Young Volcanic Deposits of Merapi Volcano and shallow groundwater table, which can result in saturated soil during an earthquake. The research was conducted to assess the potential hazards of liquefaction. The data used in this research includes geological maps, groundwater depth maps, fault distance maps, river distance maps, and slope maps. The method used is the Analytical Hierarchy Process (AHP) to determine the weight of each parameter utilized, employing Geographic Information System software to overlay maps based on the obtained weight values, allowing the liquefaction threat potential map to be classified into high, medium, and low threats. According to the findings of this study, the lowland area between the Bedog and Opak rivers has a high liquefaction potential due to the presence of Young Volcanic Deposits of Merapi Volcano going back to the Quaternary epoch and a relatively shallow groundwater table. In contrast, the hilly terrain west of the Bedog River and east of the Opak River has a low liquefaction potential due to Tertiary sedimentary rocks and a deeper groundwater table
LITERATURE REVIEW ON CO-FIRING OF SUB BITUMINOUS COAL AND BIOMASS FOR GREENHOUSE GAS EMISSION MITIGATION Nasution, Rizki Khoiriah
KURVATEK Vol 9 No 2 (2024): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v9i2.5429

Abstract

The overuse of fossil fuels has led to global warming and air pollution due to greenhouse gas emissions, particularly CO2. The toxic effects of coal combustion can be reduced by mixing coal with biomass, which is called the co-firing method. This study aims to analyze the use of co-firing using various types of biomass based on previous studies. The results show that different biomass blending ratios affect the emission reduction significantly. Mixing palm kernel shell biomass at a ratio of 10% biomass and 90% coal reduced emissions by 20%, while mixing mesua ferrea tree biomass and sawdust at a ratio of 75% coal and 25% biomass reduced emissions by 45%. The use of empty fruit bunch biomass at a ratio of 30% biomass and 70% coal can reduce CO2 emissions by 72.14%. Overall, co-firing proved effective in reducing greenhouse gas emissions and accelerating the transition to renewable energy, although its effectiveness depends on the type of biomass and the blending ratio.
SIMULASI PROSES PENGECORAN DALAM TAHAPAN REVERSE ENGINEERING TOOLPOST MESIN BUBUT KONVENSIONAL Dwiyanto, Agus; Hasanudin; Setiawan, Muhammad Diki; Kurniawan
KURVATEK Vol 9 No 2 (2024): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v9i2.5478

Abstract

Reverse engineering is an innovation in product development. Existing products are analyzed for further development or performance enhancement. This research focuses on the application of reverse engineering methods to create a toolpost, considering the need for toolpost spare parts for conventional lathes, which still relies on imports and is often unavailable in the market due to the discontinuation of manufacturers. The stages involved include gathering product information, analyzing functional features, measuring and modeling the toolpost, and conducting manufacturability analysis through casting simulation. This casting simulation aims to identify potential defects before the toolpost design is realized in a finished product. The simulation results indicate a total porosity defect of 2%, with defect locations identified in the gating system area and the hole area of the toolpost. Although defects are present, the percentage and locations of these defects are deemed unlikely to affect the functionality of the toolpost. The optimal pouring time is 2.38 seconds, and cooling time is 201.3 seconds to prevent cracking and deformation.
THE IMPACT OF TOTAL MOISTURE AND ASH ON CALORIFIC VALUE: COAL RESEARCH IN BERAU SUB-BASIN, EAST KALIMANTAN Sugiarto, Wahyu; Muljana, Budi; Syafri, Ildrem; Rizal, Yan; Prasetya, Muhammad Nurul Huda
KURVATEK Vol 10 No 1 (2025): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v10i1.5519

Abstract

Coal quality is one of the key factors in determining the effectiveness of processing and utilization. Coal quality assessment involves analyzing physical and chemical aspects to determine its characteristics. Coal quality is also influenced by geological conditions at the mining site, which affect the quality and amount of carbon in the coal. To ensure consistency, it is necessary to implement coal quality control based on physical and chemical parameters from the mining process in the pit to storage in the stockpile. Analysis of the effect of total moisture and ash on the calorific value of coal is the purpose of this study. The method used is a ROM (Run of Mine) coal sample located at the stockpile location. The relationship between Total Moisture and the calorific value of coal shows a negative linear correlation where the influence value for a 1% increase in Total Moisture is -71.343 kcal/kg and so is between Ash and the calorific value of coal 1% increase in Ash is -82.588 kcal/kg, which shows a negative linear correlation. Total Moisture increases by 1%, reducing the calorific value of coal by 71 kcal/kg, and increasing Ash content by 1% reduces the calorific value of coal by 83 kcal/kg.
THE INFLUENCE OF STAKEHOLDERS MANAGEMENT ON TRUST IN CONSTRUCTION PROJECTS Sukindrawati, Buddewi
KURVATEK Vol 10 No 1 (2025): Energy Management and Sustainable Environment
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v10i1.5521

Abstract

Stakeholders are groups or individuals who can influence or be influenced by the achievement of organizational goals. Stakeholder management is identified as the process by which the project team manages stakeholder needs and ensures their goals are achieved. The purpose of this study is to examine factors that influence stakeholder management on trust in construction projects that have an impact on project success. The research method used is a quantitative method with a total of 124 respondents in contracting companies in the Yogyakarta Special Region. The analytical method used is multiple linear regression analysis with the help of a computer program data processing tool SPSS 25.0.. The results of the research on the factors that influence stakeholder management on trust in construction projects are prescriptive stakeholders management (X1), intuitive trust (X2), competence trust (X4), honesty (X5), integrity trust (X3), and communication (X6). The result of the analysis states that the most dominant variable which significantly influences the prescriptive stakeholder management (X1), hence it is important for stakeholders mapping, identification, classification, and monitoring from the start of the project