Center for Scientific Publication
Not a member yet
4029 research outputs found
Sort by
Rheology Analysis of 3D Printed Geopolymer Based on High Calcium Fly Ash
Get PDFThe advancement of 3D concrete printing has focused on automation research in recent decades. 3D printing technology is adequate to reduce waste and improve efficiency for construction. Former research on 3D concrete printing used hydration cement based on ordinary Portland cement (OPC), which was not environmentally friendly. An alternative material to overcome problems with hydrated cement mortar is a geopolymer. Geopolymer mortar based on 3D printing is still in its infancy. Mechanical and rheological properties are the key parameters of this technology: yield stress, shear stress, and viscosity. The flow characteristics of 3D concrete printing represented the ability of material transfer along the system of the 3D printing machine. This research utilizes type C fly ash waste as the primary material for making geopolymer 3D-printed concrete. Variations of 8, 10, and 12 M of NaOH concentration were used to investigate the relationship between workability and quality of the geopolymer mortar. Workability testing of 3D concrete printing consists of several parameters: pumpability, extrudability, and buildability. Material identification, including rheology and flowability, is carried out to determine mortar specimens' pumpability, extrudability, and buildability. Several test approaches, such as slump flow, slump, shape retention, and rheometer tests using the vane shear approach method, were conducted to identify the rheological characteristics and flowability of the material. Based on testing of the material's workability, 10 M NaOH concentration variation is the most suitable material for future 3D printing material. The workability of 10 M NaOH is 177.5 mm and the the copressive strength is 25.84 Mpa. This variation meet ACI 318/318R – 14 criterion for building structure
Optimalization Of Water Cooled Chiller Through Real-Time Data Analysis
Get PDFBuilding heating, ventilation, and air conditioning (HVAC) systems are among the most critical facilities with the most significant energy consumption. This article is based on the issues faced by PT X regarding the importance of visual analytics in energy audits and the performance evaluation of water-cooled chillers and cooling towers. The research methodology used is descriptive qualitative with a quantitative approach, where primary data is obtained based on observations of the machines owned by PT X. The approach taken involves the application of spreadsheets as a system for processing operational data and Looker Studio for real-time data visualization, aimed at understanding performance and energy consumption. The research results show that visualization with the Looker Studio platform provides a solution for PT X to improve the efficiency and effectiveness of the company's performance. In addition, the analysis conducted over six months on the coefficient of performance of a 2,000 TR water-cooled chiller showed a highest value of 21.5 and a lowest value of 13.31, while the highest efficiency of the cooling tower reached 98% and the lowest was 74%
Evaluation Prototype of B30 Diesel Fuel Heater Using Arduino
Get PDFUtilizing B30 as diesel fuel has the advantage of being heated to a specific temperature. Manually setting the temperature during the heating and fuel-filling process in the heating tank causes fuel performance to become less effective and efficient. This research aims to evaluate the capability of the prototype as a B30 fuel heater. The research method was carried out experimentally by testing variables for the temperature sensor (DS28B20), distance sensor (VL53LOX), heater control system, fuel filling system, and performance of the B30 diesel fuel heater prototype on a 7 HP single-cylinder diesel engine. The research results show that the fuel heater prototype can regulate the desired temperature and fill the heating tank automatically. The fuel temperature tested starts from 280C to 650C with an average multiple of 50C and tolerances of +20C and -10C. At the same time, it can automatically fill fuel from the main tank to the heating tank set from 800 ml to 1200 ml. B30 performance on a 7 HP single-cylinder diesel engine with 100 ml of fuel heated at 280C - 650C each shows the longest fuel consumption time at 350C and the fastest at 450C
The 'Tri Hita Karana' Ecotourism Approach For Sustainable Marine Resource Management And Tourism in Bali
Get PDFMarine ecotourism in Bali is vital for integrating environmental conservation, cultural preservation, and community empowerment. Despite its potential, sustainability efforts face significant challenges, including coral reef degradation, coastal erosion, marine pollution, and gaps in policy implementation. This study aims to evaluate the application of the Tri Hita Karana philosophy as a holistic framework to address these challenges in Bali’s marine ecotourism sector. A literature review method was used, synthesizing peer-reviewed studies, government reports, and case examples from major ecotourism sites such as Nusa Penida and Perancak Mangrove Forest. The results demonstrate that the Tri Hita Karana philosophy effectively integrates ecological, social, and cultural dimensions. Successful initiatives include coral reef restoration and community-based conservation programs that enhance biodiversity and support local economies. However, challenges such as inconsistent policy enforcement, visitor overcapacity, and infrastructure pressures remain significant. This study concludes that adaptive management strategies, including capacity assessments, collaborative governance, and technology integration, are essential to ensure the long-term sustainability of marine ecotourism in Bali. The findings contribute to the global discourse on sustainable tourism, offering Tri Hita Karana as a model adaptable to other culturally rich and ecologically sensitive regions
The external controller solutions (ECS) based on programmable logic controller with humanmachine interface: A case study for the water level simulator plant
Get PDFThe External Controller Solutions (ECS) is designed with the flexibility and able to be integrated with various plants. The ECS has been built using PLC and HMI. Several tests have been carried out in developing this ECS, including testing Digital Input/Output (DI/DO) and Analog Input/Output (AI/AO) voltages. This ECS be able to control up-to 8 devices simultaneously with the data refresh time interval of 100 ms and be able to handle up-to 10,000 operating cycles within 24 hours without significant performance degradation. ECS performance is very good, proven by the results showing that the system runs well within 20-35 °C of temperatures range and 20%-80% of humidity. To show the advantage of ECS, it has already been integrated on the Water Level Simulator (WLS) plant and successfully controlled the flow through the VSD at 54 RPM/Hz in range of 15-30 Hz
Investigating Design Patterns Impact on Application Performance and Complexity
Get PDFMany studies in the literature have a premise that design patterns improve the quality of object-oriented software systems. Considerable research has been devoted to re-designing the system to improve software quality, mainly on its maintainability and reliability. Less attention has been paid to evaluating the impact of the performance efficiency quality factor. This research investigates the impact of design patterns on application performance and complexity. It is, therefore, beneficial to evaluate whether the design patterns may improve its performance and complexity or even decrease it. The research demonstrates scientific evidence in quantitative values through experimentation on a case study to present its influences. This paper uses an object-oriented enterprise project named SIA as a case study. Some issues related to design patterns are addressed. The selection of the design pattern is based on the application context issue. Three attributes related to performance efficiency are evaluated: time behavior, resource utilization, and capacity measures. The complexity is also evaluated. We use Apache JMeter and Java Mission Control as tools to support experimentation. The experiment results show that design patterns may decrease the quality of time behavior and resource utilization whilst they may increase the quality of capacity measures and complexity to a significant degree
The Influence of Forced and Natural Convection on the Sensory Characteristics of Dried Fish
Get PDFIndonesia is one of the countries with the largest archipelagos in the world, boasting an abundant wealth of natural biodiversity. One of these resources is fisheries. The production of dried fish is one of the community's efforts to increase the selling price of fish. The dried fish produced by the community is usually sold in traditional markets and has few buyers due to the lack of attention to the quality of the dried fish. To increase buyers' interest in dried fish, the quality must be improved. The aim of this study is to enhance the production system and quality of dried fish through the use of drying equipment with different drying methods, namely natural convection and forced convection drying systems. In natural convection, the drying process utilizes the movement of air flows caused by density differences, while in forced convection drying, the air flow rate is controlled with the help of a fan. This study involves the use of four variations of air velocity that will be tested: 1 m/s, 2 m/s, 3 m/s, and a gradual reduction from an initial speed of 3 m/s, decreasing by 1 m/s every 3 hours of drying until reaching 1 m/s. Drying is then continued at an air flow rate of 1 m/s until the desired moisture content is achieved. The results of the study indicate that the use of natural convection and forced convection drying methods affects the drying rate and the final product quality, including color, texture, and taste. From the results obtained, the use of forced convection drying method with a gradual reduction in air velocity proved to be the best treatment, with a drying rate of 0.036 kg/h, yielding the best final quality in terms of color, texture, and taste
Reliability of Jacket-Type Structure Considering the Reserve Strength Ratio (RSR)
Get PDFAccording to the International Energy Agency (IEA), the projected global energy demand will continue to increase by 45% by 2030, with an average growth rate of about 1.6% per year. Oil and gas are estimated to fulfil about 80% of the world's energy needs. One facility that supports oil and gas exploitation is an offshore structure of the jacket-type platform. The challenge in building a jacket platform is the cost and reliability of the structure. Costs must be kept to a minimum to maintain stable production prices. Offshore structures are designed to withstand extreme wave loads that can cause the collapse of individual components or the entire structure. So, it is necessary to analyze the ultimate strength of the jacket structure. Therefore, the author will conduct an ultimate strength analysis using the Non-Linear Pushover Analysis method to obtain the Reserve Strength Ratio (RSR). After that, a reliability analysis is carried out to determine the reliability of the structure under ultimate conditions using the Monte Carlo Simulation (MCS) method. The pushover analysis results in an RSR on the structure of 9.33. The results of the analysis of the reliability of the structure are 0.9999
Multi-Objective Optimization for Topological Shipyard Facility Layout using NSGA-II
Get PDFThe increasing complexity in ship construction due to larger vessel sizes has placed significant pressure on the shipbuilding industry to enhance efficiency and reduce costs. This paper focuses on optimizing shipyard facility layouts by minimizing material handling costs (MHC) and area costs (AC) using a topological approach for unequal areas. The objective is to develop a layout that reduces these costs while addressing gaps in previous research, which often assumed uniform department sizes. The proposed method employs the Non-Dominated Sorting Genetic Algorithm-II (NSGA-II), a heuristic algorithm designed for multi-objective optimization. Unlike previous models, this approach allows for variability in department sizes, aligning more closely with real-world conditions. The layout optimization is conducted by considering adjacency and non-adjacency constraints, ensuring an effective arrangement of shipyard departments. The results demonstrate that the proposed method significantly reduces both MHC and AC, leading to a more efficient and cost-effective shipyard layout. The dual-objective approach not only narrows the gap between topological and geometric models but also optimizes space utilization within the shipyard, making it a practical solution for modern shipbuilding challenges
Analisis Nilai Inflasi Bulanan Indonesia Menggunakan Regresi Nonparametrik Estimator Kernel
Get PDFHigh levels of inflation are plaguing Indonesian society. Inflation occurs due to price increases as indicated by the increase in most expenditure group indices. This can lead to a higher poverty rate in Indonesia. This study aims to identify the best method that can be used to estimate Indonesia's monthly inflation value based on a nonparametric regression approach with a kernel estimator and analyze the results of predicting Indonesia's monthly inflation value for the next four months. The data used in this study is secondary data sourced from Bank Indonesia, with the variable used is the value of Indonesian inflation during the period January 2019 to July 2024. The collected data were analyzed using descriptive statistics and analytical statistics in the form of nonparametric regression with kernel estimators and predictions using kernel estimator and non-seasonal ARIMA methods. The results showed that triweight kernel regression was the best kernel function model with a minimum bandwidth value of 1.214, value of 99.990, MSE of 0.00016, and MAPE of 0.348%. The results of data prediction for the next thirteen months provide that triweight kernel estimator was better than non seasonal ARIMA method, with a MAPE value of 10.92%, so that the nonparametric regression method with the triweight kernel function is good or accurate in predicting data, which also can be used to analyze and predict Indonesia's monthly inflation data