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This study was conducted based on the crucial role of diesel generator engines as the primary source of electrical power on board ships, making their operational reliability essential. One of the factors influencing generator engine performance is lubricating oil temperature. Excessive lubricating oil temperature may reduce lubrication effectiveness, increase friction between moving components, and lower engine efficiency. Therefore, this research aimed to identify the causes of high lubricating oil temperature in diesel generator engines and determine appropriate corrective actions. The study employed a descriptive quantitative approach. Data were collected through direct observation, interviews, and documentation during sea practice aboard MV. CL FLANDERS from 4 July 2024 to 5 July 2025. The data were analyzed using simple linear regression to examine the relationship between generator load and lubricating oil temperature. The findings revealed that generator load had a significant effect on the increase in lubricating oil temperature. Under normal operating conditions, the lubricating oil temperature ranged from 60°C to 72°C, while under abnormal conditions it increased to between 68°C and 81°C. The abnormal rise in temperature was mainly caused by cooling system problems, particularly a dirty LO cooler, scale deposits on the sea water pump impeller, and blockage in the cooling capillary pipes. The regression equation under normal conditions was Y = 45 + 0.30X, whereas under abnormal conditions it was Y = 53.5 + 0.30X. Elevated lubricating oil temperature resulted in lower oil viscosity, higher fuel consumption, and reduced diesel generator engine performance. Therefore, regular maintenance of the LO cooler, sea water pump, and continuous temperature monitoring are necessary to maintain optimum engine performance.

Travertine is a non-marine carbonate rock precipitated from calcium- and bicarbonate-rich waters, commonly associated with hot springs, streams, and lakes in tectonically active regions. This study presents a systematic literature review of travertine deposit characteristics, encompassing mineralogical composition, geochemical signatures, petrographic textures, morphological types, isotopic properties, biotic–abiotic controls on formation, early diagenesis, and petrophysical implications. The synthesis indicates that travertine is predominantly composed of calcite, with aragonite forming under conditions of elevated temperature, high Mg/Ca ratios, and rapid CO₂ degassing. Travertines display exceptional textural diversity, ranging from abiotic crystalline crusts to microbially mediated fabrics such as shrub, peloidal, and stromatolitic structures. Major morphologies include fissure ridges, mounds, terraces, cascades, and slopes, strongly governed by tectonic setting, topography, hydrology, and substrate geology. Stable isotopes (δ¹³C and δ¹⁸O), strontium isotopes, trace elements, and REE patterns effectively constrain fluid provenance and distinguish thermogene from meteogene travertines. Microbial activity plays a crucial role in biomineralization, influencing precipitation rates, crystal morphology, and lamination patterns. Early diagenetic processes occurring during active deposition may significantly modify primary fabrics and geochemical signals. Travertine petrophysical properties exhibit distinctive porosity–velocity relationships, making them valuable analogues for subsurface carbonate reservoirs. This review highlights that travertines record complex interactions among physical, chemical, biological, and geological processes and hold significant value for paleoenvironmental reconstruction and carbonate reservoir studies.

Facies analysis and thin-section petrography are complementary and essential approaches for determining the lithological characteristics of deep-water deposits. Deep-water sediments are formed by diverse depositional processes such as turbidity currents, debris flows, slumps, and pelagic suspension settling, producing a wide range of lithofacies with distinctive textural, compositional, and sedimentary structural attributes. This literature review synthesizes studies that apply facies analysis and thin-section petrography to characterize deep-water deposits across various basins and geological ages worldwide. Field-based facies analysis emphasizes lithology, sedimentary structures, bed geometry, and vertical–lateral facies relationships to reconstruct depositional environments. In contrast, thin-section petrography provides microscopic insights into mineral composition, grain texture, cement types, porosity, and diagenetic features that are not observable in the field. The integration of these methods, often combined with advanced techniques such as XRD, SEM, and geochemical analyses, has proven effective in distinguishing lithofacies, understanding sedimentary processes, and evaluating reservoir quality. The review highlights that grain size, sorting, cement type, pore-throat size, and diagenetic processes are key controls on lithological characteristics and reservoir potential in deep-water systems. Therefore, the combined application of facies analysis and thin-section petrography provides a comprehensive framework for interpreting deep-water sedimentary systems.

Cholelithiasis is the formation of hardened bile deposits within the gallbladder due to an imbalance in the chemical composition of bile, which can cause symptoms ranging from abdominal pain to serious complications such as cholecystitis, biliary obstruction, and gallbladder infection. This study aimed to determine the relationship between patient characteristics and the length of hospital stay in cholelithiasis patients at Cut Meutia General Hospital. This study used an analytical observational design with a cross-sectional approach and a retrospective study, employing a total sampling technique with 50 patients. The results showed that most patients were female (52.0%), with the largest age group being late elderly (28.0%). The most common surgical technique was laparoscopic cholecystectomy (42.0%), and the majority of patients received surgical management (60.0%). Bivariate analysis using the Chi-Square test showed significant relationships between age (p=0.000), gender (p=0.044), surgical technique (p=0.029), and management (p=0.045) with the length of hospital stay in cholelithiasis patients. The conclusion of this study is that there is a relationship between patient characteristics and the length of hospital stay in cholelithiasis patients.

The global energy crisis and climate change are driving the development of biodiesel as a renewable energy source. Graphite as an additive shows significant potential in improving the efficiency and reducing emissions of biodiesel. This study maps graphite-biodiesel research in Southeast Asia using a meta analysis of systematic reviews of 68 publications from Scopus, Web of Science, and ScienceDirect from 2015-2024. The results show that Malaysia leads in publication contributions (32%), followed by Thailand (28%) and Indonesia (18%). The optimal graphite concentration of 50 ppm increases brake thermal efficiency by 8.3% and reduces CO (15.7%), HC (12.4%), and smoke (18.9%) emissions, although there is an increase in NOx (6.8%). Palm oil methyl ester dominated the research (56%). Indonesia has strategic opportunities with abundant feedstock and graphite deposits, but faces challenges in research infrastructure, limited international collaboration, and the absence of an integrated national roadmap. Infrastructure investment, human resource strengthening, and industry academia collaboration are needed to accelerate national biodiesel research.