Numerical Analisys of Segmental Box Girder’s Stress with Eccentric Tendon Anchoring on Balanced Cantilever Box Girder Bridge

Diagonal crack damage on the web of balanced cantilever box girder bridges has frequently occurred worldwide, including in Indonesia. Previous studies have shown that these cracks can result from additional shear stress caused by prestressed tendon anchoring. In this study, an analysis was conducted using a 2D element model verified through a numerical approach. The evaluation of box girder web stress values was used to assess the potential for cracking and confirm the results of crack mapping conducted on site. The research found that shear stress from prestressed tendon anchoring increases the total shear stress on the box girder web by up to 46.6% of the total shear stress value. The distribution of shear stress from prestressed tendon anchoring is concentrated in the anchoring areas on the top slab and bottom slab sides of the box girder web. The evaluation of principal tensile stress shows that the observed crack locations in the field correspond to areas where the principal tensile stress values exceed the allowable design limit

Ethylene Evaporation Rate Analysis in the Storage Tank and Boil-Off Gas Dispersion: Case Study in PT Lotte Chemical Titan Nusantara

As a primary raw material at PT Lotte Chemical Titan Nusantara (LCTN), ethylene storage is 12,000 tons in icy conditions (- 103.6 °C and 40-80 mbarg) before processing into polyethylene. Ethylene evaporation is inevitable. Therefore, the proper handled of ethylene needs to be settled. The evaporation rate or Boil-Off Rate (BOR) of ethylene is predicted to be 0.0705-0.0730% vol/day, and the Boil-Off Gas (BOG) is 9.41-9.76 tons per day (at 21-40 °C and a tank liquid level of 15.41 meters, approx. 52.51% volume of tank). The BOR is a predicted value of the percentage of volume evaporated daily. When the liquid level is increased, the BOR rate will also be increased. The size of any leaks dramatically impacts the gas dispersion radius. A leak with a 10 mm size at wind speeds of 5 and 10 km/hr resulted in the radius distance of BOG dispersion being 8.2 and 7.7 m, respectively. When the leak hole is ten times bigger, ca. 100 mm, the radius is eight times wider. Fortunately, gas releases happen well above ground level (15.5 meters), causing the cloud to rise, keeping personnel safe. Too low liquid levels ramp up evaporation, risking shortages, while overfilling increases BOG, raising the chance of spills and safety hazards. Hence, managing these variables is crucial to keep operations smooth and safe

INTEGRATION, RELATION, AND RECREATION: RETHINKING ARCHITECTURAL PROGRAMMING

This study rethinks architectural programming as an innovative process, emphasizing the integration of contextual elements, the relational blending of multiple functions, and the adaptive reuse of existing spaces as recreation over time. Moving beyond the traditional understanding of programming as problem-finding-solving, this research redefines it as a dynamic framework bridging theoretical insights and practical design applications. Through a qualitative case study methodology, the paper examines three landmark projects with similar functions by Bjarke Ingels Group—8 House, The Mountain, and Urban Rigger—to explore the transformative potential of programming. The analysis positions programming as an integrative tool that aligns spatial, functional, and contextual dynamics to address both immediate and future architectural challenges. Program mixing with relational functions is conceptualized as a strategic approach that harmonizes diverse functions within a single design, fostering innovative and hybrid solutions. Adaptive reuse, reframed as a multi-time design response, focuses on revitalizing existing structures to meet evolving societal and environmental needs. These case studies illustrate how programming establishes a dynamic framework that enables architects to creatively reimagine constraints as opportunities. By emphasizing the principles of design analysis—realization, organization, and integration—this research contributes to the discourse on programming as a catalyst for architectural innovation and transformation. It proposes a shift in practice that highlights programming as a generative and responsive framework, inspiring a rethinking of architectural methodologies in the face of contemporary challenges

Analysis of the Use of a Combination of Soil Embankment and Lightweight Material (Foam Mortar) as an Alternative to Slab on Pile Construction Case Study: Rengat-Pekanbaru Toll Road Construction Project Section Lingkar Pekanbaru-Junction Pekanbaru Sta 19

The soil condition on the Rengat - Pekanbaru Toll Road Sta 193+ 025 - Sta 193+400 which passes through oil palm plantations, swamp areas, and the Siak River, consists of a compressible layer as thick as 7.0 meters. To handle the problem, a 375 m long slab on pile construction was planned with a construction time of 3 months. However, the design was costly; therefore, alternative planning using ordinary piles and a combination of ordinary and lightweight piles was required. The rate of settlement at the study site did not meet the requirements for t = 1 year (< 2cm/year) or t = 10 years (< 10cm/10 years). Therefore, it is necessary to install PVDs with an installation distance of 1.0 meter and a length of 7.0 m. The stability analysis showed that as the percentage of foam mortar increases, the SF value increases. The bearing capacity of the subgrade was increased by installing geotextiles; the number of geotextile layers required at each site varied depending on the height of the embankment and the combination of soil + foam mortar, the thicker the foam mortar, the less geotextile layers were required. The number of reinforcing piles was also planned according to the thickness of the soil and foam mortar variations; the thicker the foam mortar, the less piles were required. In terms of cost, the slab on pile replacement structures that provide savings are geotextile-reinforced soil backfill and a combination of soil backfill with 25% thick foam mortar. Each of these replacement structures provides savings of Rp 40 billion (without foam mortar) and Rp 12.1 billion (with 25% thick foam mortar). For the implementation time, both methods require the same completion time as slab on pile which is 3.5 months

Slope Stability Analysis Under Dry-Wetting Cycle Conditions (Case Study: Landslide Countermeasure of Batas Pidie/Aceh Besar - Batas Kota Sigli)

A landslide occurred on National Road Section Bts. Pidie/Aceh Besar - Bts. Kota Sigli Sta. 0+500 during the peak of the rainy season has resulted in the disruption of traffic lanes. Soil samples were obtained from the landslide site for inclusion in the testing process. The laboratory tests encompass a range of physical and mechanical parameters and also dry-wetting procedures. The result shows that the topsoil layer consists of sandy silty clay with medium plasticity. Then, a dry-wetting cycle was conducted to simulate the dry and rainy season by introducing and reducing water content from the initial condition (wi) to saturated (wsat) and to airdried (wairdry) with 25%, 50%, 75%, and 100% interval. The results showed a decrease in unconfined compressive strength (qu) by 22.70% and negative pore water pressure (-Uw) by 53.14%. Slope stability analysis found that the slope was stable after the landslide with an FS value of 1.380 and increased to 1.410 when there was the addition of slab on pile road construction. The addition of rainfall variations for 3 and 5 hours is insignificant to the stability of the slope due to the groundwater table being too deep to affect pore water pressure

Viscosity Modeling and Prediction of Amorphophallus oncophyllus and Sapindus rarak Using Machine Learning Methods

Viscosity plays an important role in regulating the mobility of fluids injected into the reservoir to increase the efficiency of oil sweeping. This study discusses the application of Machine Learning methods, namely ANN and ANFIS, to model the correlation of physical properties of Amorphophallus oncophyllus and Sapindus rarak solutions. The purpose of this study is to obtain a correlation to determine the viscosity of the polymer solutions. The data used include viscosity measurements for 21 samples of Amorphophallus oncophyllus and Sapindus rarak solutions with variations in concentration and salinity. The data is augmented by digitization for modeling. The results show that both Machine Learning methods can estimate viscosity values well. Very accurate results are achieved by applying ANN and ANFIS with average correlation coefficients of 0.997240 and 0.995124, respectively

Oxide Dispersion Strengthened Steels: Precipitation Kinetics and Matrix Phase Transformation

This study presents a comprehensive investigation of the microstructural features, precipitation kinetics, phase transformations, and mechanical properties of Oxide Dispersion Strengthened (ODS) steels, with a focus on the impact of Y₂O₃ particle dispersion. Detailed microstructural analysis using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) revealed a fine and uniform distribution of Y₂O₃ particles, averaging 10-15 nm in size, which contributed to significant grain refinement to 5-7 µm. The precipitation kinetics, examined through Differential Scanning Calorimetry (DSC) and dilatometry, showed a diffusion-controlled mechanism with an activation energy of 230 kJ/mol. The dispersed oxide particles delayed the austenite-to-martensite transformation, stabilizing the austenitic phase at higher temperatures, as confirmed by in-situ High-Temperature X-ray Diffraction (HT-XRD). Mechanical tests demonstrated a hardness of 320 HV and a tensile strength of 600 MPa, with a total elongation of 12%. These results highlight the effectiveness of oxide dispersion in enhancing the mechanical strength and thermal stability of ODS steels. The findings suggest that ODS steels are highly suitable for high-performance applications, particularly in environments such as nuclear reactors and aerospace, where high temperature, radiation resistance, and mechanical durability are critical. Future work should explore the long-term stability of these materials under operational conditions to further optimize their performance

Seismic Hazard Identification On North Banda Arc Region Using Gutenberg-Richter Law

North Banda Arc region has high risk of significant earthquake due its complex tectonic configuration. in order to assess seismic hazard potential on north Banda Arc region, Gutenberg-Richter (G-R) Law is applied using Earthquake catalogue from 1970 to 2023. The results are G-R parameters including Mc, a, and b, where the the spatial parameters  (a and b values) and temporal parameter (b-value) are applied to investigate the seismic hazard in the north Banda Arc Region. The spatial results show that two regions with high risk to release stress in strong earthquake are on eastern Seram Island and between eastern Buru and western Seram Island including its smaller island nearby. On the other side, temporal earthquake shows decreasing b-value indicates increasing effective stress that could lead to strong earthquake

Optimization of Bioethanol Production From Chlorella Vulgaris With Ca2+,Mg2+, and Zn2+ Ion Suplements Through Separated Hydrolysis and Fermentation Using Respon Surface Methodology

Indonesia, with its wealth of natural resources, has the potential to develop bioethanol as an alternative to diminishing fossil energy sources. Third-generation bioethanol is a form of renewable energy and an environmentally friendly fuel derived from non-conventional biomass resources, particularly from microorganisms such as algae and cyanobacteria. This study focuses on optimizing the bioethanol production process from the microalga Chlorella vulgaris using the Separated Hydrolysis and Fermentation (SHF) method, with the addition of Ca2+, Mg2+, and Zn2+ ions to enhance bioethanol yield and concentration. The research procedure includes raw material pretreatment, acid hydrolysis, liquefaction, saccharification, fermentation, and distillation. The distillate samples are analyzed for bioethanol concentration using a refractometer and bioethanol density with a pycnometer. The effect of added medium components on the fermentation process is statistically analyzed using Analysis of Variance (ANOVA) in MINITAB Statistical Software and Response Surface Methodology (RSM) in DESIGN EXPERT 13. Statistical optimization of the fermentation process is performed using Central Composite Design (CCD). ANOVA analysis reveals significance with a P-Value <0.0001 for bioethanol yield and concentration. Optimization results indicate an optimal yield of 17.087% with a concentration of 165.592 g/L, achieved with the addition of Ca2+ at 164.755 ppm, Mg2+ at 146.279 ppm, and Zn2+ at 38.516 ppm

Comparison of Ensemble Learning Methods in Classifying Unbalanced Data on the Bank Marketing Dataset

The banking industry is experiencing rapid growth, particularly in telemarketing strategies to increase product and service sales. Despite widespread use, these strategies need higher success rates due to data imbalance, where fewer customers accept offers than those who reject them. This study evaluates machine learning algorithms, including Random Forest, Gradient Boosting, Extra Trees, and AdaBoost, without and handling imbalanced data using the Random Over-Sampling Examples (ROSE) method. The evaluation covers accuracy, precision, recall, F1-score, and AUC of the ROC curve. Results indicate that Random Forest and AdaBoost consistently perform well, with Random Forest maintaining a high accuracy of 91.00% after handling imbalanced data. Gradient Boosting and Extra Trees improve in precision post-oversampling. All models exhibit high AUC values, close to 0.94, demonstrating excellent differentiation between positive and negative classes. The study concludes that addressing data imbalance enhances model performance, making these models suitable for effective telemarketing strategies in the banking sector