Publication Search

Supercapacitor electrode material bassed on Pelepah Enceng Gondok Activated Carbon (KAPEG have been developed for increasing the performance of the supercapacitor application. The activated carbon surface structure and its properties strongly depend on the pyrolysis temperature and the type of activation methods. The bamboo carbon has been fabricated using pyrolysis method. The KAPEG was produced using chemical activation with H3PO4 as activation agent with variation of temperature activation 750oc have been carried out. Characterization of the surface structure (functional groups vibration) of bamboo carbon (CB) pyrolysis and the Pelepah enceng Gonddok activated carbon (KAPEG) were carried out using FTIR. The aim of this research is  to identify the functional groups vibration. he FTIR rssults shows absorption peeaks of functional groups of -OH, C=O, C-O, C-H and C-C vibration. The increasing of wavenumber of absorption peaks of functional groups -OH stretching, C=O stretching and C-H indicate that the functional groups bond for KAPEG samples becomes more stronger than for KPEG sample. The conclusion of this research are: the increasing of wavenumber of absorption peaks for functional groups indicates of more stronger of functional groups bond.

The pitcher plant (Nepenthes sp.) is a type of predatory plant typically found in tropical regions and has a pitcher structure designed to attack insects. The pitcher's structure acts as a small ecosystem that supports a variety of microorganisms, both those living on the surface (epiphytes) and those within the tissue (endophytes). This study aimed to extract and identify microorganisms present on the surface and interior of the pitcher plant. Samples were taken from peat swamps and separated using Nutrient Agar (NA) for bacteria and Potato Dextrose Agar (PDA) for fungi. The discovery process involved examining morphological characteristics both visually and under a microscope. The results revealed differences in the types of microorganisms between the outside and inside of the pitcher, influenced by the microenvironmental conditions in each area. These findings can serve as a foundation for further study of the bioactive potential of microorganisms from the pitcher plant.

The Dandu Bridge is one of the important infrastructures that functions as a land transportation link on the Suko-Sowominangun section, Lamongan Regency. The current condition shows that the bridge surface has suffered a lot of damage in the form of holes that can interfere with the smooth flow of traffic and endanger the safety of road users. Therefore, regular maintenance is needed so that the function of the bridge as a public facility remains optimal. One of the maintenance methods used is the Detailed Bridge Inspection Report (LPMJ), which aims to identify the condition of the bridge components as a whole. Field work practices carried out by students of the Lamongan Institute of Technology and Business in March-April 2025 are a means to understand the factors that cause damage. The results of the observation show that the damage is not only caused by structural factors, but also by non-structural aspects such as lack of awareness of road users and lack of communication with the surrounding community. Therefore, intensive education is needed for the community regarding the importance of maintaining the sustainability of the bridge's function, including the installation of proper traffic signs to minimize damage. In the LPMJ method, the upper structure components examined include floor plates, girders, and joints. Meanwhile, the lower structure includes pillars, abutments, and foundations. The bridge equipment that was observed included sidewalks, waterways, and railings. Maintenance should not only be focused on physical improvements, but also on social management that involves the active participation of the community, especially in areas with high traffic intensity. In conclusion, the maintenance efforts of the Dandu Bridge require an integrated approach that combines technical improvements and social empowerment, so that the sustainability of its function can be maintained for the long term.

Batang Bungo River faces severe pollution from domestic waste and illegal gold mining, which has led to an increase in skin diseases and diarrhea among residents of Tanjung Gedang, exacerbated by poor physical-chemical water quality, including low pH and high levels of Total Suspended Solids (TSS) and Chemical Oxygen Demand (COD), all of which foster the growth of pathogenic microorganisme. This study aimed to identify bacteria and fungi present in Batang Bungo River water, characterizing their colony morphology and microscopic structures to understand the impact of pollution on microbial communities. The methodology involved serial dilution of water samples, followed by inoculation onto Nutrient Agar (NA) media using the pour plate technique, and incubation at 37°C for 24-48 hours. Macroscopic observations of colonies (color, shape, texture) were performed, and representative colonies were stained with crystal violet for microscopic observation at 1000x magnification to identify cellular and hyphal structures. The results indicated the presence of various microorganisms, including Gram-positive bacteria, filamentous fungi, and possibly protozoa, with colonies exhibiting characteristics such as off-white color, rough surfaces, and irregular edges. Microscopic examination after crystal violet staining revealed rod-shaped (bacilli), spherical (cocci) structures, and branched filamentous structures resembling hyphae, consistent with a mixture of bacteria and filamentous fungi. The identification of pathogens like Clostridium, Dermatophilus, and Escherichia coli in previous studies, coupled with the poor water quality, confirms significant microbiological and chemical contamination. Crystal violet proved effective as a stain for microscopic identification of microorganism structures. In conclusion, the water quality of Batang Bungo River is highly concerning and requires serious attention for monitoring and management to safeguard public health and the river ecosystem.  

This study aims to design and evaluate lipstick preparations by utilizing solid paraffin as the base ingredient and lanolin as an emollient and stabilizer. Solid paraffin was chosen because of its dense properties at room temperature and having the ability to form a stable lipstick structure. In addition, paraffin can provide a smooth, durable surface, and provide good smearing power. On the other hand, lanolin is known as a natural emollient ingredient that functions to moisturize and protect the lips from dryness. Lanolin also has water-retaining properties (occlusive) so that lip moisture is maintained even if the lipstick is used for a long time. The process of making lipstick is carried out by the melting method using indirect heating to maintain the stability of the material and prevent color and aroma degradation. All materials are accurately weighed, then put into beaker glass and heated over three legs using a Bunsen lamp. During heating, the ingredients are gently stirred so that all the components, including solid paraffin and lanolin, melt and mix homogeneously. Once the mixture reaches the desired consistency, the formula is poured into the lipstick mold and allowed to set at room temperature until ready for use. The results of the evaluation test showed that the combination of solid paraffin and lanolin was able to create lipstick with an optimal solid texture, even color, not easy to crack, and had a smooth application power on the surface of the lips. Lanolin plays a big role in providing a soft, moisturizing effect and adding a natural shine to the lips. Meanwhile, solid paraffin helps maintain the shape of the lipstick so that it doesn't break easily when applied. This study also highlights the importance of comparing the composition of ingredients to produce lipsticks that have a stable melting point, good application power, and appropriate adhesion.  

Photogrammetry is a widely used technique in reverse engineering that utilizes photographs taken from multiple angles to capture the geometric structure and surface textures of physical objects. This method has gained popularity due to its cost-effectiveness and time efficiency compared to more expensive alternatives such as laser scanning. However, one of the primary limitations of photogrammetry is its susceptibility to dimensional deviations that can affect the accuracy of the resulting 3D model. Among the influential parameters, the number of photos taken and the camera’s shutter speed play a crucial role in determining the level of geometric precision. This study aims to analyze the effect of the number of photos and shutter speed on dimensional deviation in 3D reconstruction results. It also seeks to determine the optimal combination of these parameters to enhance model accuracy in reverse engineering applications. The research method used is an experimental approach, in which variations of photo quantity and shutter speed are applied during image capture. The resulting photographs are processed into a 3D model using Computer-Aided Design (CAD) software and compared with the actual dimensions of the object under study. The findings reveal that both the number of photos and shutter speed significantly influence dimensional accuracy, both individually and interactively. The best results were obtained using a combination of 48 photos with a shutter speed of 0.020 seconds, yielding the smallest deviation of 7.6 mm. In contrast, a combination of 36 photos with the same shutter speed produced the highest deviation at 10.6 mm. ANOVA analysis yielded a p-value < 0.05 and an R² value of 94.21%, confirming the importance of selecting appropriate imaging parameters for accurate photogrammetry outcomes.

Bekasam is a traditional Indonesian fermented food produced through spontaneous fermentation involving microorganisms, particularly lactic acid bacteria (LAB). LAB plays a crucial role in the fermentation process by producing lactic acid, which lowers pH, inhibits pathogenic microbial growth, and enhances flavor and food safety. This study aimed to identify and characterize LAB isolated from fermented snakehead fish (Channa striata) based on Gram staining and colony morphology. The research began with bacterial isolation using NA Nutrient Agar, followed by macroscopic observation of colony characteristics including shape, edge, elevation, color, and size. Subsequently, Gram staining was performed to determine the cell wall structure and microscopic morphology of the bacteria. The results showed that the bacterial isolates from bekasam generally had circular colonies, white to cream in color, smooth surface, and were Gram-positive rod-shaped cells. In conclusion, bekasam from snakehead fish contains dominant lactic acid bacteria with distinctive colony morphology and Gram-positive characteristics, indicating potential as a natural starter culture for food fermentation.

One type of efficient and widely used heat exchanger is the Plate and Frame Heat Exchanger (PFHE). PFHE is a device designed to increase the efficiency of heat exchange through a structure of plates assembled together. This design allows a large heat exchange surface area in a relatively small space, creating an efficient environment for heat transfer. This study took the Plate and Frame type Heat Exchanger object, while the purpose of this study was to determine the performance of the Heat Exchanger in the Sea water & Cooling Water system at PT. Eni. The research methods used were the Observation method, Interview method (Question and Answer), and Literature review. The results of the study showed that the performance of the Heat Exchanger in the Sea water & Cooling Water system at PT. Eni runs according to the desired design. The operating temperature line remains below the maximum limit set, and indicates the performance of the heat exchanger in very good condition. This reflects the optimal heat exchange results in Cooling Water. In accordance with the design operating parameters, the achievement of heat exchange in the minimum range of 4 - 5 ℃ and the maximum limit of redistribution temperature in Cooling Water does not exceed 45 ℃, which indicates that this system operates according to the desired standards

This study aims to analyze students’ difficulties in understanding the concept of Stokes’ Theorem in the Vector Calculus course. The method used is a descriptive qualitative approach with data collected through semi-structured interviews with mathematics education students who have studied the topic. The results show that students struggle to comprehend the relationship between line integrals and surface integrals, as well as to connect the concept of curl with vector direction in three-dimensional space. Limited understanding of prerequisite material and the lack of visual media further exacerbate these difficulties. Students reported that learning methods based on visualization and group discussion were helpful. This study recommends the use of contextual learning strategies and interactive media to improve students’ understanding of abstract concepts in Stokes’ Theorem.

mathematical instruction often lacks relevance to students’ real-life contexts, necessitating more meaningful and contextualized approaches. This study aims to integrate geometric concepts and ethnomathematics through the utilization of ketupat a traditional Indonesian cultural artifact as a culturally grounded instructional medium. A descriptive qualitative method was employed, using literature review and contextual observation of the geometric structure of ketupat. The findings reveal that ketupat encompasses geometric elements such as symmetry, three-dimensional forms, woven patterns, and calculations of volume and surface area. Moreover, ketupat holds significant symbolic meaning within Indonesian culture, making it a relevant bridge between mathematical concepts and local values. The study concludes that using ketupat as a contextual medium enhances students’ conceptual understanding of geometry and strengthens the integration of cultural values within mathematics education.

Ground-mounted solar panels are directly exposed to environmental conditions, particularly wind, making structural design essential. While wind tunnel experiments have been a primary research method, they are costly and time-consuming. Computational Fluid Dynamics (CFD) simulations provide an efficient alternative by accurately modeling fluid-structure interactions, allowing for detailed aerodynamic analysis without physical testing. This study examines a solar panel configuration of 2×18 (1700×1200 mm panels) under a wind speed of 30 m/s at a height of 10 m. Wind direction variations (0°, 30°, 60°, 90°, 120°, 150°, 180°) significantly impact aerodynamic behavior. Drag Force analysis reveals that frontal wind (0°) generates the highest drag, while lateral wind (90°) has the least effect. Surface Pressure and Surface Coefficient (Cp) analysis indicate maximum pressure at 0°, where Cp values are highest, highlighting a pronounced pressure differential. At 90°, pressure distribution is more uniform, reducing aerodynamic impact. At 180°, rear-side pressure remains influential but lower than frontal exposure.

The piping installation process involves connecting pipes based on ASME standards using Schedule 20 and Schedule 40 pipes with diameters ranging from 2” to 32”. The pipe joining process is carried out using either electric welding or argon welding methods. Gas Tungsten Arc Welding (GTAW) is applied, utilizing LINCOLN 6010 electrodes for the root pass and LINCOLN 6011 electrodes for the fill pass. After welding, the newly joined pipes must be inspected by a Quality Control (QC) officer using X-ray radiographic testing to detect any internal welding defects. Following radiographic inspection, sandblasting is performed using silica sand once the pipe surface has been properly ground and smoothed. The piping installation follows a circular connection pattern, meaning all pipe ends are continuously joined without interruption. Finally, the piping system is installed on a piperack structure and connected to a storage tank for fluid containment.

Deforestation in Indonesia's hilly regions has a significant impact on increasing the rate of erosion and sedimentation. This study aims to systematically examine the effects of deforestation on erosion and sedimentation processes and evaluate conservation approaches used to mitigate these impacts. The method employed is a literature review of various relevant national and international studies, focusing on tropical upland areas in Indonesia. The analysis reveals that the conversion of forests into agricultural land, plantations, and settlements results in the loss of vegetative cover, which plays a critical role in stabilizing soil particles and regulating surface runoff. The resulting impacts include increased erosion rates, soil structure degradation, and elevated sedimentation in water bodies, which deteriorate water quality, reduce reservoir capacity, and harm aquatic ecosystems such as coral reefs and mangrove forests. Effective conservation approaches include vegetative techniques such as reforestation and agroforestry, as well as mechanical techniques such as terracing and check dams. The main recommendation from this review is the need for integrated conservation policies, community participation, and the mapping of vulnerable areas to achieve sustainable and adaptive land management in Indonesia’s hilly regions.

The utilization of clam shells as adsorbents has attracted considerable attention due to their ability to adsorb contaminants such as heavy metals, hazardous substances, and oil. Clam shells, which are composed mainly of calcium carbonate (CaCO₃), possess a porous structure that favors adsorption. Calcium carbonate imparts alkaline properties that neutralize acidic effluents and promote the formation of precipitates. Physical and chemical modifications can enhance the surface area and porosity of the shell, thereby enlarging the active sites for contaminant sorption. Clam shells heavy metals such as Pb, Cd, Hg, organic substances and can be used for oil spill remediation due to their hydrophobic and oleophilic properties. The calcination process converts the shells into a material that contaminants such as TSS, COD, and BOD. This utilization not only mitigates pollution but also creates opportunities for adsorbent products with economic value, especially in coastal areas where shell waste is abundant. However, this application must take into account ecological and health impacts, as overharvesting and non-environmentally friendly processing can damage the ecosystem. A sustainable approach with environmentally friendly regulations and technologies is essential to maximize the benefits of clam shells as adsorbents.  

The major work of the Cijurey Dam Project Package III is located in Bogor Regency, West Java Province, which is a spillway structure consisting of iron structures and concrete structures. To achieve the right quality, on time, on cost, and zero accidents, concrete casting calculations and appropriate work implementation methods are required. This research method uses descriptive with quantitative and qualitative approaches. The stages of concrete casting work for the Cijurey Dam spillway structure's launch channel consist of preparation, measuring the launch channel block boundaries, lean concrete work, reinforcement work, formwork panel preparation, formwork panel installation, waterstop and dowel bar work, concrete sampling and slump test, concrete casting, concrete curing/maintenance, formwork dismantling, and finishing of tierod holes. The results of the study showed that the calculations for casting the concrete channel were a large volume of concrete channel casting of 135,000 m3, concrete material requirements (in the form of: 1,115,100 sacks of cement, 58,050 m3 of sand, 1,020,600 m3 of gravel, and 29,025,000 liters of water), channel formwork (surface area) of 27,675 m2, productivity of casting the concrete channel launcher of 24 m3/hour or 193 m3/day, and the efficiency of casting the concrete channel launcher time of around 125% (25% faster than planned). Meanwhile, the stages of work implementation for channel concrete casting include preparation work, measurement work for the boundaries of the launcher channel blocks, lean concrete work, reinforcement work, formwork panel preparation work, formwork lubrication work, formwork panel installation work, waterstop and dowel bar work, concrete sampling and slump test work, channel concrete casting work, concrete curing/maintenance work, formwork dismantling work, and finishing work for tierod holes. In addition, an inter-segment locking system with a shear key is used to overcome problems with the concrete pump, joint inspections are carried out during mobilization, routine inspections, repairs and replacement of the concrete pump.

This study describes the manufacture of modified composites from recycled HDPE plastic waste and TKKS fibers. The comparison of matrix composition with TKKS fibers used is (70:30); (80:20) and (90:10) %. The mixing process of HDPE with OPEFB was carried out using the melt blending method and extruded to obtain composite pellets. Composite characterization obtained high tensile strength in HDPE composites: OPEFB ratio (70:30) % of 36.50 Mpa, while the tensile strength of HDPE: OPEFB ratio (80:20) and HDPE: OPEFB ratio (90:10) % were obtained respectively 23.50 MPa and 26.50 MPa. The results of the surface structure test with SEM showed that there was a bond between the HDPE matrix and TKKS fibers which was marked by a brittle fracture shape on the surface of the composite and the fibers were not uniformly broken. The impact test results of HDPE composite: OPEFB ratio (80:20) % have a high impact value of 0.363168 Joules. The FT-IR test results show deformation of C-H vibrations and pyranose C-O-C which are typical of OPEFB at wave numbers 1070.49 & 1151.50 cm- and intermolecular O-H bending in TKKS at wave numbers 3672.47 cm-. The TGA test results of HDPE composite: OPEFB ratio (70:30) and HDPE: TKKS (80:20) obtained degradation temperature values (Te) of 535.57ᴼC and 529.74ᴼC, respectively.

In 2022, a significant fire incident occurred at a steel tower structure in an industrial plant in Lampung, Indonesia, raising serious concerns about the structural integrity and serviceability of the affected steel framework. Fire exposure is known to alter the properties of steel, weaken bolt pretension, and cause defects in welds, underscoring the necessity of thorough post-fire assessments. Nondestructive testing (NDT) methods are crucial in evaluating the safety and stability of structures after fire exposure, as they can detect potential weaknesses without compromising the material further. This study employed two field inspection methods: the bolt torque test and dye penetrant inspection (DPI). A total of 21 bolts (Tor-1 to Tor-21) were tested for their integrity. The results showed that, while all bolts were present, more than half were found to be loosened, indicating the need for re-tightening to restore the specified torque and maintain the required preload for the bolted connections. In addition, 20 welded joints (DP-1 to DP-20) were examined using DPI to detect surface defects. The inspection revealed that 10 welds (50%) exhibited surface defects exceeding 5 mm in length, indicating areas where the welds had been compromised by the fire exposure. Seven welds (35%) were found to be in acceptable condition, while 2 welds (10%) were incomplete or had poor bonding. These findings suggest that while the bolted joints can be restored through corrective re-tightening, the welded joints require more extensive evaluation, local repairs, or even rewelding to ensure their structural integrity. This study highlights the importance of NDT methods in post-fire structural evaluations and recommends periodic inspections and targeted rehabilitation to ensure the long-term reliability and safety of industrial steel structures.

Bio-inspired engineering is a rapidly growing field that applies principles found in nature to develop innovative solutions in structural engineering, materials science, and robotics. This paper explores biomimicry in various disciplines, such as self-cleaning surfaces inspired by lotus leaves, energy-efficient building designs modeled after termite mounds, and ultra-lightweight yet durable materials inspired by spider silk. The study highlights the role of computational modeling in replicating biological structures and discusses the challenges of translating natural efficiencies into engineered systems. Additionally, this research examines the environmental impact of bio-inspired materials and their potential to replace conventional, resource-intensive materials in industries such as construction, aerospace, and biomedical engineering.

The seismic and magnetic data are well known for the investigation of tectonic structures and their directions on surface and subsurface, a methodological approach integrated the seismic and magnetic data interpretation combined with field measurement on cracked building and its underlying substratum, represented by Agadez sandstones and basement. The extraction of seismic lineaments from West African seismic map showed the seismic directions oriented NW-SE (N135 to N160°), passing through the studied area. The structural interpretation of magnetic map show that the Agadez region is also affected by the subsurface lineaments mainly oriented in NW-SE (N135°) directions, which are similar to the identified seismic lineaments in the same zone. A structural study carried out on the Agadez sandstones and the underlying basement, showed that faults and fractures oriented N120° to N165°, affect both the basement of the Aïr Mountains and the sandstone for­mations on which the city of Agadez is built. These observations showed that building cracking in Agadez region has a higher propagation tendency according to the directions rang­ing from NW-SE (N135°) to NNW-SSE (N165°). Therefore, the buildings cracking has a stronger propagation component according to these mean directions those are not recommended for building. To prevent and reduce the risks related to building cracking in Agadez region, it is highly recommended to build in the minor directions of cracking propagation which correspond to NE and SW directions.

Abstract Rainfall or discharge data is obtained from the river basin authority by conducting hydrological analysis using the Nakayashu Synthetic Unit Hydrograph method to obtain the peak flood discharge and performing a dependable flow analysis (Q80%) using probability equations. On January 2, 2020 there was a flash flood that destroyed at least 1,410 houses, 30 bridges and hydraulic buildings located in the ciberang river flow among them is the PDAM row water intake structure. The need for hydrological studies to predict flood discharge as data needed in planning the stability of hydraulic building structures and determining the water surface elevation for intake operations. The results of the hydrological study of the Ciberang watershed obtained the design flood discharge values for specific return period of Q2 = 205,1 m3/s, Q5 = 340,5 m3/s, Q10 = 406,4 m3/s, Q25 = 475,6 m3/s, Q50 = 518,1 m3/s, Q100 = 549,6 m3/s. The estimated historical flash flood discharge that occurred in early 2020 in the ciberang river upstream of the Karian reservoir based on the testimony of residents as high as 8 meters is equivalent to the design discharge for Q25, which is 475.6 m³/s. The results of the dependable discharge (Q80%) calculations for the Ciberang watershed indicate that the minimum discharge occurs in September at 7.22 m³/s, while the maximum discharge occurs in February at 37.0 m³/s.   Keywords: Hidrology, Rainfall Plan, Flood Discharge Plan, Dependable Discharge.