Vol. 56 No. 6 (2024)

This study examined the arc and line shapes produced in the fault ruptures of the 2016 Mw7.8 Kaikoura earthquake in New Zealand and the 2023 Mw7.8 and Mw7.6 East Anatolian Fault earthquakes in Turkey-Syria. Theoretical fault mechanisms and physical laws of movement were used to interpret the conceptual geometry of the arc and line shapes, and kinematics force movement. Using computer-aided design (CAD) on the Universal Transverse Mercator (UTM) metric projection, this paper presents earthquake parameters defining the fault geometry, including straight lines and arc shapes with specific…

This study utilized coffee cherry residues, which is an abundantly available source of biomass in Indonesia. One of the methods to utilize coffee plantation residues effectively is wet torrefaction. This method is well-known as a hydrothermal method, where the biomass conversion process uses liquid as a medium and reactant in the process. The objective of this work was to develop an effective procedure for converting coffee agro-waste into marketable products using hydrothermal technology. The information related to changes in physical and thermal properties were explored in this work. To…

The global rise in carbon emissions presents a rising challenge for current and future generations. In the pursuit of zero carbon emissions, ammonia (NH3) has emerged as an attractive alternative energy source. Ammonia offers a carbon-free fuel option with a higher energy density than liquid hydrogen while maintaining ease of transport and storage. However, ammonia still has its drawbacks, such as a high autoignition temperature, slow burning velocity, and low heating value, that demand further investigation of its combustion characteristics. This experiment was done to study the effect of…

This study aimed to evaluate the impact of different additive percentages on the mechanical properties and durability of warm-mix asphalt. Two types of additives, Sasobit as an organic additive and Zeolite as a water-based additive, along with bituminous foam, were used at 2%, 4%, and 6% levels in modified asphalt mixes. Rutting resistance, moisture susceptibility, and cracking resistance were assessed using semi-circular bending tests, dynamic creep tests, and indirect tensile strength tests, respectively. Additionally, a two-dimensional performance interaction diagram was developed. The…

Averrhoa bilimbi fruit extract was utilized as a reducing and capping agent in the biosynthesis of zinc oxide nanoparticles, with an emphasis on the effects of in-situ deagglomeration on physical properties and antibiofilm activity against Escherichia coli. The study explored various biosynthesis parameters, namely deagglomeration method (physical vs chemical), temperature (30, 60 ℃), and zinc precursor-to-extract volumetric ratio (0.5 and 2). High purity crystalline ZnO nanoparticles were obtained by calcining biosynthesis precipitates at 375 ℃. The resulting particles consisted of the…

This study investigated the synergistic application of ultrasonic (UL) and microbubble (MB) technologies for the disinfection of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Optimal conditions for both techniques were determined through a comprehensive experimental design, resulting in an effective disinfection rate of 100% as assessed by the ten-fold dilution spread plate count method. The study evaluated three key parameters of the UL/MB system, i.e., UL duration time, MB duration time, and gas flow rate within the ranges of 30-60 sec, 30-60 sec, and 15-30 ml/min,…

The aim of this study was to evaluate the fatigue life of Rumpiang Bridge in Barito Kuala Regency, South Kalimantan, which features a 200-meter-long steel truss arch structure. Fatigue evaluation was performed by referencing the AASHTO Manual for Bridge Evaluation 2018 and the provisions in RSNI T-03-2005 and using the cumulative fatigue damage method. Actual traffic loads based on weigh-in-motion (WIM) data obtained from Prof. Dr. Ir. Sutami Road in Lebak Regency, Banten over a seven-day period were simulated using structural modeling in MIDAS Civil 2022. The results indicated that Rumpiang…

Pyrolysis is a commonly used method to produce main products such as bio-char, bio-oil and syngas. However, the practical use of syngas as a fuel is currently constrained by suboptimal properties and the necessity for specialized storage. This study investigated the impact of using syngas directly as an additional fuel for heating the pyrolysis reactor on process parameters and the properties of the resulting bio-char products. The experiment was conducted using two process variations: (i) pyrolysis utilizing syngas as fuel for co-firing with LPG, and (ii) pyrolysis using only LPG as fuel.…

An innovative nonlinear enhancement technique that integrates the cloud model with Fuzzy Analytic Hierarchy Process (FAHP) is presented in this study. For the first time, this paper introduces TBM tunnelling parameters as evaluation indicators for tunnel construction collapse risk. Precise risk level thresholds are set for each indicator, establishing a comprehensive TBM construction collapse risk assessment system. Within this system, the cloud model is applied to accurately depict membership degrees, transcending the limitations of traditional reliance on functional formulas. Furthermore,…

The evolution of structural design standards, from empirical approaches to modern precision, has significantly impacted seismic evaluation and building safety. Indonesia’s adoption of seismic standards in 2002, aligned with global practices like ASCE, introduced notable shifts in seismic design philosophy. This study offers a novel comparison of the seismic performance of a forty-story office building in Jakarta designed under SNI 1726:2002 versus the updated SNI 1726:2019. The unique focus of this research lies in evaluating how the shift from a uniform risk philosophy to a uniform hazard…

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