Proceeding of the International Conference on Tropical Studies and Its Applications (ICTROPS)
Proceeding of the International Conference on Tropical Studies and Its Applications (ICTROPS), is organized by the University of Mulawarman in collaboration with the Islamic Development Bank (IsDB) and the Ministry of Education and Culture of the Republic of Indonesia.
Traffic Impact Analysis of Hotel & Convention Center Development on National Road in Malang City
The rapid growth of tourism in Malang City has increased traffic volume around commercial corridors, particularly near hotel and convention facilities. This study analyzes the traffic impact of the CDR-INN Hotel & Convention construction at Jaksa Agung Suprapto Street using Traffic Impact Analysis (TIA) framework. The analysis includes trip generation, origin-destination matrix, and road performance evaluated through PTV Vissim microsimulation for existing, construction, initial operation, and five-year operation conditions. Results indicate existing intersections experience moderate to high congestion. Construction activities significantly increase delays and saturation. Initial and five-year operations show substantial traffic load decreasing service levels without mitigation. Do Something scenarios—including signal optimization, turn restrictions, continuous-flow lanes, and selective widening—improve performance. The study concludes integrated engineering interventions are essential to maintain traffic performance and support sustainable urban mobility.
Muhammad Ibadurrahman Arrasyid Supriyanto
Copyright (c) 2026 International Conference on Tropical Studies (ICTROPS)
Modeling and Simulation of Nanofiltration for Separating Calcium, Magnesium, and Sulfate from Rejected Brine to Produce High-Purity Salt
Rejected brine from seawater desalination is a concentrated stream rich in NaCl but containing elevated levels of Ca²⁺, Mg²⁺, and SO₄²⁻ that limit its use as a feed for high-purity industrial salt. This study aims to evaluate whether nanofiltration can selectively remove these divalent ions and to provide a mechanistic description of ion transport and process performance. A steady-state, isothermal model of a commercial spiral-wound KeenSen NF1-4040F element is developed using the Donnan-Steric Pore Model with Dielectric Exclusion coupled to the Extended Nernst–Planck equations. Radial transport inside the pores is coupled with axial mass balances for the feed and permeate streams, and solved numerically over feed pressures of 2.5 - 12.5 bar and inlet flow rates of 1.08 - 3.60 m³·h⁻¹. The simulations predict that permeate-water flux increases linearly with pressure, while along the module the retentate flow rate decreases and the permeate flow rate increases linearly with axial position. Stage recovery rises with pressure but decreases with increasing inlet flow rate. Mechanistic flux decomposition indicates that convection dominates cation transport, particularly for Na⁺, whereas diffusion and electromigration contribute more strongly to the transport of anions. Under the investigated conditions, sulfate and magnesium achieve rejections above 97%, calcium about 96%, while chloride and sodium show lower but still significant rejections. Overall, the model suggests that operating at moderate-to-high pressure and moderate inlet flow can maximise recovery while maintaining high divalent-ion rejection, supporting the use of nanofiltration as a pre-purification step to upgrade rejected brine to a higher-purity salt feedstock.
The Effect of Asphalt Modification With PET Plastic Waste and Latex Rubber on AC-WC Asphalt Pavement Mixture with Local Aggregate from East Kalimantan
The need for Asphalt materials that yield a high stability value to prevent road damage and improve driving safety and comfort will continue to increase. However, the availability of asphalt is dwindling because it is a non-renewable material. This study aims to determine the effect of adding PET plastic waste and latex rubber as a partial replacement for asphalt in the AC-WC mixture. This research was carried out by testing asphalt penetration 60/70 with 3 types of addition of partial asphalt replacement materials and making 63 samples, of which 45 samples with 3 types of mixtures and 5 variations of asphalt content for the Marshall test, as well as 18 samples for the Marshall Immersion test. The test method used is based on the General Specifications for Highways 2010 Revision 3. This modified asphalt mixture research summarizes that the mixture with the addition of 3% PET plastic waste obtained a VMA value of 17.90%, a VFA of 75.16%, a VIM of 4.44%, a stability of 2901 kg, and a flow of 3.1 mm, at mixture with the addition of 3% latex rubber obtained VMA 17.93%, VFA 80.76%, VIM 3.45%, stability 2335 kg, and flow 3.2 mm, in a mixture with the addition of latex rubber 6% obtained VMA 18.07 %, VFA 79.53%, VIM 3.70%, stability 2176 kg, and flow 3.1 mm. As well as the results of the Marshall Immersion test on asphalt mixtures with the addition of PET plastic waste and latex rubber as a partial replacement for asphalt, with the addition of 3% PET plastic waste, 3% latex rubber, and 6% latex rubber of the total weight of the asphalt mixture, the residual Marshall stability value has been obtained. each of 81.2%, 94.5% and 90.7%. So, the addition of latex rubber as a partial replacement for asphalt can make the mixture more resistant and stronger, reducing damage from water and weather.
The Potential of Eco-Enzyme as an Environmentally Friendly Product for Organic Waste Management
Eco-enzyme is a fermented liquid produced from organic kitchen waste and has gained attention as a sustainable, low-cost alternative for wastewater treatment. This study evaluates the effectiveness of eco-enzyme derived from household fruit and vegetable scraps in improving the physical quality of industrial wastewater. Eco-enzyme was produced using a 1:3:10 ratio of organic waste, brown sugar, and water and fermented for six months under semi-anaerobic conditions. Industrial wastewater samples were treated with eco-enzyme at a dosage of 10% v/v and analyzed before and after 48 hours of contact time. Key parameters measured included pH, Total Solid (TS), Total Dissolved Solid (TDS), and Total Suspended Solid (TSS). Results showed a shift in pH from 8.0 to 7.0, TS reduction from 470.1 mg/L to 310.5 mg/L, TDS from 380.0 mg/L to 215.5 mg/L, and TSS from 95.0 mg/L to 50.0 mg/L. These reductions indicate partial degradation and settling of solid contaminants influenced by enzymatic hydrolysis and organic acids present in eco-enzyme. In addition, eco-enzyme application on chili plants increased plant height from 4.0 cm (control) to 5.7 cm after ten weeks. These findings suggest that eco-enzyme has promising potential for small-scale wastewater treatment and agricultural enhancement. However, the absence of replicate measurements and limited parameters constitute significant limitations. Further research is recommended to optimize dosage, fermentation variables, and large-scale application.
Sustainable Exploration of Mine Water Residuals for Drinking Water Resilience in Jahab, Tenggarong, Kutai Kartanegara Regency
Mine water residuals (void) represent a potential raw water source for remote communities, such as in Kelurahan Jahab, Kecamatan Tenggarong, Kabupaten Kutai Kartanegara. After more than ten years of inactivity, the former open-pit coal mine site operated by PT Multi Harapan Utama has undergone natural stabilization processes, resulting in neutral pH, low Total Dissolved Solids (TDS), and heavy metal concentrations below drinking water quality thresholds. However, laboratory analysis reveals extreme microbiological contamination, with Total Coliform reaching 1,240 MPN/100mL, although E. coli is <20 MPN/100mL. Currently, local residents extract water directly from the void using portable pumps and sell it to other households at IDR 65,000 per 1,500 liters. This practice lacks post-extraction treatment, posing significant risks of recontamination and adverse health impacts. This study aims to design a three-stage hybrid water treatment system—comprising aeration, multistage filtration, and ultraviolet (UV) disinfection—that is effective, affordable, and manageable by a Village-Owned Enterprise (BUMDes). The methodology integrates laboratory analysis, field surveys, in-depth interviews, and engineering design based on localized data. Water quality data were obtained from the official Environmental Laboratory Report by DLHK Kutai Kartanegara. Research findings demonstrate that the hybrid system effectively removes residual particulates, oxidizes volatile organic compounds, and eliminates pathogens without forming carcinogenic Disinfection By-Products (DBPs). Integration of a 2,500-watt solar power system ensures off-grid operation and enhances energy resilience. System sustainability is secured through a community Willingness to Pay (WTP) model ranging from IDR 50,000 to IDR 150,000 per month, transparently managed by BUMDes. These results prove that mine water residuals, once perceived as environmental liabilities, can be transformed into strategic rinking water assets.
Utilization of Empty Oil Palm Fruit Bunches as a Source of Nanocrystalline Cellulose through the Acetic Acid Hydrolysis Method
This study investigates the production of nanocrystalline cellulose (CNC) derived from oil palm empty fruit bunches (OPEFB) using acetic acid hydrolysis as a greener alternative to conventional mineral-acid-based hydrolysis. The effects of acetic acid concentration (2–10%), hydrolysis time (2–6 h), and temperature (160–200°C) were examined regarding CNC yield, particle size, zeta potential, chemical structure, crystallinity, and morphology. The result shows the CNC yield increased from 78.17% to 87.39% at 8% acid concentration, then decreased at 10% due to over-hydrolysis. With the variation of acetic acid concentration from 2 to 10%, the particle size was reduced from 1200 nm to 639 nm, while zeta potential values ranged from –18.62 to –22.80 mV indicating moderate to good colloidal stability. Fourier Transform Infra-Red (FTIR) confirmed the removal of lignin and hemicellulose. XRD analysis showed sharper peaks at 2θ ≈ 22.6°, signifying increased crystallinity, and SEM revealed rod-like CNC structures with smoother surfaces at higher acid concentrations. The results demonstrate that OPEFB is a promising raw material for environmentally friendly CNC production, with optimal performance obtained at 8–10% acetic acid.
Industrial Gas Production Capacity Planning Strategy using System Dynamics to Support the IKN Project
The increasing demand for industrial gas in East Kalimantan, driven by the construction of the new capital city (IKN) and rapid industrial growth, poses challenges for producers in meeting consumer needs effectively. PT XYZ, a key industrial gas provider, has struggled to balance its production capacity with market demand, leading to recurring backlog orders. This study aims to analyze the oxygen production capacity of PT XYZ using the System Dynamics method. A dynamic model was developed to capture the relationships between production variables, demand drivers, and external influences. The simulation of the current system revealed a consistent shortfall in meeting oxygen demand, with a projected backlog reaching 1,197,198 m³ by 2029. To address this, three policy scenarios were proposed: increasing the number of production machines, outsourcing production, and a combination of both. The simulation results indicated that the third scenario, which combines equipment expansion and outsourcing, provides the most sustainable solution. It eliminates backlog by the end of 2029 and generates a profit of IDR 20,289,156,114. These findings highlight the importance of strategic capacity planning and the effectiveness of integrated approaches in aligning production with future industrial gas demand, particularly in support of national infrastructure development.
The Effect of Random-Access Memory Capacity on the Performance of FL Studio (Fruity Loops) on Laptops
This study discusses the effect of RAM capacity on FL Studio performance on laptop devices. This study was conducted by dividing 3 different RAM configurations (32GB, 16GB, & 8GB) to be tested one by one. This study conducted an artificial experiment by creating a music project and dividing it into two variations in the form of native and third-party software plugins to see the difference in workload and the RAM requirements for each project in FL Studio. Performance data was measured from three scenarios (load, playback, and render). It was found that the third-party project (based on a large sample library) that had been created required approximately 25GB of RAM to run optimally. With a 32GB RAM configuration, the render duration was 135.0s and the load duration was 113s. In the playback scenario, the project ran optimally and CPU usage was below 50%. With a 16GB configuration, playback was possible but experienced a bottleneck as seen from the SSD read activity (average) increasing to 16.8 MB/s. The rendering process was also successful, but slower at 154.3 seconds. In the 8GB configuration, there was a performance failure in the load scenario (305 seconds), making it impossible to proceed to the playback and real-time rendering scenarios. In contrast, the native project (synthesizer) required approximately 9.4GB of RAM with rendering in 67.3 seconds. This study concluded that RAM requirements affect projects with third-party plugins (especially those based on large sample libraries).
Integrated Risk Analysis and Delay Prediction in Construction Projects using XGBoost, Monte Carlo Simulation, and Rule-Based Reasoning
Infrastructure development relies heavily on timely construction project execution; however, schedule delays remain a critical challenge that escalates costs and compromises quality. This study develops an intelligent decision support system integrating qualitative risk assessment with quantitative predictive modeling to analyze and mitigate schedule delay risks. A comprehensive risk matrix survey of 25 construction professionals identifies weather conditions as the most dominant delay factor (risk score: 18.3), establishing the empirical foundation for the system architecture. The framework utilizes a unified dataset of 11,000 records combining daily project operational data—including progress, work volume, labor deployment, material receipts, and equipment usage—with meteorological data from BMKG covering 2021–2023. Data preprocessing encompassed cleaning, feature engineering, and SMOTE method to address class imbalance. The Extreme Gradient Boosting (XGBoost) algorithm classifies daily task feasibility as safe, at-risk, or delayed. Monte Carlo simulation with 10,000 iterations quantifies duration uncertainty due to weather variability and productivity fluctuations, while a Rule-Based Reasoning (RBR) module generates automated mitigation recommendations including rescheduling and resource reallocation. Evaluation using Repeated K-Fold Cross Validation demonstrates robust performance: 95.6% accuracy, 93.2% precision, 94.1% recall, and 93.7% F1-score. Monte Carlo analysis reveals schedule variations between −10% and +25% relative to planned durations. The RBR module successfully reduces average project delays by 21.5% and improves labor efficiency by 14.2%. These findings demonstrate that integrating risk analysis, machine learning, and stochastic simulation within a unified computational framework significantly enhances predictive accuracy and enables proactive delay mitigation, supporting adaptive decision-making under dynamic weather and operational conditions.
Effect of Time and Different Catalysts on Biodiesel Production using Co-Solvent Method
A major problem in converting Crude Palm Oil (CPO) into biodiesel is typically high free fatty acid (FFA) content, which leads to low conversion efficiency and excessive soap formation during processing. Therefore, this study aims to reduce FFA content and improve biodiesel yield through esterification using an H₂SO₄ catalyst and methanol, which aims to convert free fatty acids into esters, followed by transesterification with the NaOH catalyst that aims to convert triglycerides into esters. Variations in catalyst concentrations are treated in order to compare the effectiveness of acid catalysts that work to reduce acid numbers (FFA%). The results of this study are samples with NaOH catalyst (120 minutes) produced biodiesel with the lowest ALB content (0.31%), compared with samples with KOH catalyst that had higher ALB levels (1.5% - 4.5%).
Analysis of Essential Oil Content from Cajeput Leaves (Melaleuca leucadendra) Using Soxhlet Extraction: Comparison of Ordinary Water and Methanol Solvents
This research aims to quantitatively analyze the essential oil content extracted from Melaleuca leucadendra leaves using the Soxhlet method, and to evaluate and compare the efficiency of ordinary water (aquadest) and methanol as solvents based on the resulting essential oil yield and the co-extracted secondary metabolite compounds (total phenolics). The study employed a comparative-experimental design focusing on two primary independent variables: the type of solvent (ordinary water and methanol) and the solvent-to-cajuput leaf ratio (1:1 and 1:2), in addition to comparing local and imported cajuput leaf types. Soxhlet extraction was consistently carried out for 190 minutes. The samples were analyzed through qualitative phytochemical screening to identify flavonoids and tannins, as well as quantitative analysis for the determination of Total Phenolic Content (TPC) using the Folin-Ciocalteu spectrophotometric method and LC/MS analysis. Test results showed that cajuput leaf extracts contain flavonoids, tannins, and phenolic compounds in all samples. Imported cajuput leaves consistently exhibited a higher content of bioactive compounds compared to local leaves. The methanol solvent proved to be more effective than distilled water across all parameters, attributed to its optimal polarity for dissolving both polar and semi-polar compounds. The most optimal condition for obtaining the highest content of secondary metabolite compounds was found to be the combination of imported leaves, methanol solvent, and a 1:6 ratio.
Analysis of β-Carotene Content in Crude Palm Oil from PT. REA Kaltim using Transesterification and Esterification Methods with UV-Vis Spectrophotometry
Crude Palm Oil (CPO) is a major source of vegetable oil containing bioactive compounds such as beta-carotene, which significantly influences the quality and nutritional value of palm oil. The beta-carotene content may change during chemical processes such as esterification and transesterification, commonly applied in biodiesel production. This study examines the effect of these processes on the beta-carotene content of CPO from PT. REA Kaltim. The esterification process utilized 0.225% sulfuric acid catalyst based on oil volume, while transesterification employed 80% sodium methoxide catalyst. Parameters observed include acid value, saponification value, and beta-carotene concentration determined using UV-Vis spectrophotometry. The analysis provides insights into the effectiveness of both chemical processes on beta-carotene stability and supports efforts to enhance the quality and added value of palm oil derivatives in the vegetable oil industry.
Preliminary Study of Breakpoint Chlorination (BPC) at Tura Tea WWTP, Samarinda
Population migration and growth in Indonesia have led to an increase in domestic wastewater production, which can reduce environmental quality if not treated properly. The main problem in this study is the high concentration of ammonia in the effluent of Tura Tea WWTP, Samarinda, which is 96 mg/L, exceeding the quality standard of Environmental Ministry of Indonesia No. 11 of 2025, which is 50 mg/L. High ammonia mixed with high chlorine is toxic and has the potential to form disinfection by-products. This study aims to evaluate the performance of wastewater management facilities and develop an optimization approach to improve effluent quality to meet quality standards. The research methods included field data collection and laboratory analysis of key parameters (TSS, BOD, COD, pH, ammonia, and total coliform) at the inlet and outlet points. The optimization process was carried out using the breakpoint chlorination method with calcium hypochlorite (Ca(OCI)2). The results showed that the optimal dose capable of effectively reducing organic pollutants was a chlorine dose of 200 mg/L, which produced a residual chlorine level of 3.55 mg/L with an ammonia removal efficiency of 80%, initially 96 mg/L to 19.2 mg/L. This study demonstrates that the chlorination-based disinfection process using calcium hypochlorite (Ca(OCI)2) in the final treatment stage can improve WWTP performance and ensure that effluent meets domestic wastewater quality standards in Indonesia.
Analysis of Dependable Flow in the Brantas Watershed using Google Earth Engine
Dependable flow analysis is crucial for water resource management, such as in the Brantas River Basin, but is often hindered by the limitations of conventional observation data (AWLR). This research demonstrates an alternative methodology by integrating the Google Earth Engine (GEE) platform with the F.J. Mock hydrological model to estimate dependable flow, using a quantitative descriptive approach in the Brantas River Basin, Blitar Regency (area 1588.79 km²). The research methodology includes the acquisition of CHIRPS satellite rainfall data (2022–2024 period) via GEE and climatological data from BMKG. Potential Evapotranspiration (ETo) was calculated using the Modified Penman Method. Both rainfall (P) and ETo data were used as inputs for the F.J. Mock model to simulate monthly discharge (Qmodel), which was then analyzed using a Flow Duration Curve (FDC) with the Weibull formula. The results successfully identified the dependable flow values: Q70 = 0.65 m³/s, Q80 = 0.19 m³/s, and Q90 = 0.07 m³/s. This study concludes that the integration of GEE for data acquisition and the F.J. Mock model for hydrological simulation provides an effective, efficient, and technology-based alternative to overcome conventional data limitations in water resource planning.
Structural Assessment of Teak Timber Beams in Heritage Buildings: Integrated Visual Inspection and FEM Analysis of OJK Central Java Office
This study presents a comprehensive structural assessment of teak wood (Tectona grandis) beams in the heritage OJK Central Java office building, integrating visual inspection techniques and Finite Element Method (FEM) analysis using LISA V.8. Field investigations revealed significant cracking (0.6–1.4 mm width) and deflection (10.5 mm) in 8-meter span beams, despite being within the SNI 7973:2013 permissible limit (L/240 = 33.33 mm). Laboratory tests characterized material properties: Modulus of Elasticity (E) = 12,600 MPa, Poisson’s ratio (ν) = 0.30–0.35, and density (ρ) = 680 kg/m³. FEM simulations validated field measurements (10.39 mm vs. 10.5 mm actual deflection) and identified critical tensile stresses (3.17 MPa) approaching the material’s allowable limit (8.5 MPa). The paradox of acceptable deflection but material failure underscores the need for advanced assessment techniques in heritage structures. FRP reinforcement is recommended to enhance load capacity while preserving architectural integrity
Geology and Groundwater Quality Analysis for Clean Water and Irrigation of Sanga-Sanga District, Kutai Kartanegara Regency, East Kalimantan Province
The research location is in two sub-districts, namely Sanga-sanga District, Samarinda City and Palaran District, Kutai Kartanegara Regency, East Kalimantan Province. This research was conducted with the aim of knowing the quality of ground water in the study area. The research method used in this research is laboratory analysis and direct survey in the field. The well water sample data used are 2 water samples which are considered to represent the research area by using purposive sampling method. The groundwater quality assessment for clean water shows that all samples are within the permissible threshold and are included in the clean water quality standard value. Then the assessment of groundwater for irrigation shows the quality of the groundwater, which is very good to good. So it meets the requirements for use as irrigation. And the groundwater assessment for the pollution index obtained the status of water quality which also meets the quality standard (good condition). Keywords: Groundwater, Pollution Index, Clean Water, irrigation
Copyright (c) 2023 International Conference on Tropical Studies (ICTROPS)
Estimation of Mangrove Carbon Stocks at Muara Badak Waters, Kutai Kartanegara
The most important ecological function of the mangrove ecosystem is to absorb and store carbon in efforts to mitigate global warming. This study aims to determine the density of mangrove species and analyze the amount of carbon stock in mangrove area at the Muara Badak Kutai Kartanegara, East Kalimantan. This research was conducted in July 2022 at two sampling stations using the line transect method. The results showed that the average mangrove density at Station I was 1,100 ind/ha and at Station II was 1,133 ind/ha, indicating that the two stations were in moderate/good condition. The estimated carbon stock of mangrove at Station I has an average carbon of 1.789 tons/ha and at Station II has an average carbon of 2.169 tons/ha. The correlation between mangrove density and mangrove carbon stock showed a close relationship with the R value is 0.9278. Keywords: Mangrove, carbon stock, mangrove density, Muara Badak The most important ecological function of the mangrove ecosystem is to absorb and store carbon in efforts to mitigate global warming. This study aims to determine the density of mangrove species and analyze the amount of carbon stock in mangrove area at the Muara Badak Kutai Kartanegara, East Kalimantan. This research was conducted in July 2022 at two sampling stations using the line transect method. The results showed that the average mangrove density at Station I was 1,100 ind/ha and at Station II was 1,133 ind/ha, indicating that the two stations were in moderate/good condition. The estimated carbon stock of mangrove at Station I has an average carbon of 1.789 tons/ha and at Station II has an average carbon of 2.169 tons/ha. The correlation between mangrove density and mangrove carbon stock showed a close relationship with the R value is 0.9278. Keywords: Mangrove, carbon stock, mangrove density, Muara Badak
Photovoltaic Power Plant Monitoring by Using Low-Cost Internet of Things (IoT): Design and Implementation
A study on the monitoring system of a photovoltaic (PV) power plant using low-cost Internet of Things (IoT) technology for monitoring electrical output (voltage and current) and environmental parameters (solar irradiance and cell temperature) to measure the performance of PV power plant has been realized. The prototype design of the monitoring system developed is the integration of several smart sensors, microcontrollers and algorithms that are able to read, send and process data in real-time. The working principle of IoT in this monitoring system is to connect sensors and devices from special systems on a public network through wired or wireless nodes. In general, IoT-based wireless systems are preferred to avoid the risks associated with wired systems. By still paying attention to the needs in the near future, where every device will be smart, automatic and connected via the internet.
Designing a Waste Power Plant (PLTSA) Prototype Based on the Type of Waste as a Renewable Energy Source
Renewable electricity from waste is one of the solution to overcome the problem of the energy crisis of fossil fuels and solutions to reduce the increasing waste population in Indonesia. The abundance of rubbish in Indonesia with the existence of Waste plant can produce enough electricity and can also reduce the problem in Indonesia itself, namely the lack of electricity in some regions. In this journal, we make a prototype of a waste power plant (PLTSa) using the incinerator method or what can be called combustion. The initial step to do is collecting reference data in the form of journals. Then the PLTSa prototype was assembled, and finally the prototype was tested. Based on the results of the prototype test conducted by comparison of different types of waste, namely used wood, dry leaves, and paper with a load of one LED. Obtained an average power of 0.1763 watts. From prototype testing that we have done, it can be concluded that the type of used wood waste that produces greater power.
The Combination of Jicama (Pachyrizus erosus L.) and Tofu and Alternative Medium for the Growth of Escherichia coli Bacteria
Bacterial growth media is necessary for bacterial culture in laboratory. Bacterial growth media is sold commercially, but its distribution has not yet reached all regions. Local raw materials that have potential to fertilize the growth of microorganisms are jicama (Pachyrhizus erosus L.) and tofu. Jicama (Pachyrhizus erosus L.) can be a source of carbohydrate nutrition and tofu as a source of protein for microbial growth. This study aims to examine the potential combination of jicama (Pachyrhizus erosus L.) and tofu as an alternative bacterial growth medium. This research is an experimental study with a descriptive approach that uses 3 tests. The bacterial inoculation method used is the pour plate method. The results showed that the natural medium of jicama (Pachyrhizus erosus L.) and the natural medium of tofu cannot be used as an alternative growth medium for escherichia bacteria. Heating in the process of making the media activates flavonoids in jicama (Pachyrhizus erosus L.) which can inhibit the growth of bacteria. The process of making tofu uses vinegar so it is acidic and bacteria are intolerant of its pH. Different methods and procedures must be carried out to produce jicama extract (Pachyrhizus erosus L.) and other non-acidic sources of protein.
The Conservation and Development Model Design of Camphor (Dryobalanapos Aromatica) Biodiversity in Sibagindar Champor Forest Pakpak Bharat District North Sumatra
Camphor trees (Dryobalanops aromatica) are one of the typical trees with a high prospect in Nusantara, especially in North Sumatra. Camphor was in high demand in the 2nd century so the price was almost equal to gold, Europe and the Middle East showed a high interest in this commodity. The camphor tree produces camphor which attracts the interest of most people. This tree grows in the forests of northern Sumatra. The International Union for the Conservation of Nature (IUCN) states that camphor has entered a very critical period and is even threatened with extinction. Therefore, it Is important to maintain and protect the existence of camphor trees by involving wider communities to grow this tree. This paper discusses the conservation and development of camphor trees in the Sibagindar camphor forest as a form of conservation of camphor biodiversity and sustainable regional economic development. This study uses a descriptive qualitative method. The first process was identifying the problems and potentials of the camphor tree and the local area. Data were analyzed to design a conservation and development model of camphor.
Using Ergonomic Checkpoints in Agriculture to Support the Improvement of Work Systems in Rubber Plantations a Case Study in CV. Eja Nursery, East Kalimantan
CV. Eja Nursery is one of the rubber plantations located in Kutai Kartanegara District, East Kalimantan. Indonesia is the second largest rubber producer in the world. Based on the initial observations it was found that there was not ergonomicwork environment at CV. Eja Nursery. Not ergonomic work environment will interfere with the productivity of farmers' work. Given the importance of ergonomics in agriculture, the International Labor Organization (ILO) in collaboration with the International Ergonomics Association (IEA) developed an ergonomics approach to improve safety and health in agriculture, which was named the Ergonomic Checkpoint in Agriculture. Based on this concern, research on the evaluation of ergonomicsworking condition is conducted in CV. Eja Nursery using Ergonomic Checkpoint in Agriculture. The results showed that 27.6% of the working conditions at CV. Eja Nursery needs improvement. This means the working conditions at CV. Nursery is mostly in accordance with ergonomics standards in agriculture. Aspects that require attention are providing welfare facilities and organization and work schedules.
Green Open Space Planning Using the Sustainable Child-Friendly Concept (Case Study: Kampung Seketeng, Sumbawa)
Green open space has various of functions that will be useful in creating environmental management balance and harmony. A decent city is not only about luxurious buildings, but also has space and facilities to support children's growth and development. The purpose of this research is to develop a green open space design in Seketeng Village, Sumbawa district. Regional design guideline is one of planning document that exists in an area to support and contribute the realization of sustainable green city. In the next stage, the design of the area can be used as a reference in the implementation of the arrangement and management of buildings/physical activities. This research was conducted using a quantitative approach. The objective is to establish a green open space that is capable of serving the activities of Child-Friendly villages in a sustainable manner, is directed at developing the function of green open spaces in achieving the elements of “nature” and “society” in each typology of green open spaces formed. The expectation of this strategy is that the green open space can be increased through urban villages and be able to serve community activities. Keywords: Design, Green Open Space, Environmental management
The Effect of Wind Speed on the Power Generated in a Wind Power Plant Prototype
Bayu or known as wind is one of several renewable energy sources that have the potential to produce electrical energy. Wind conditions that are not the same between places affect the energy produced. This wind condition is closely related to wind speed, so an experiment is needed to determine the effect of wind speed on the power generated on the PLTB prototype. The method used is to directly measure the power generated by the PLTB prototype which is loaded with different wind conditions. The results obtained with a wind speed of 3.5 m/s capable of producing an average power of 0,0188 watts, then at a wind speed of 4 m/s capable of producing an average power of 0,0241 watts, and a wind speed of 4.3 m/s capable of producing an average power of 0,0283 watts, this shows that wind speed affects the power generated.
Voltage and Current Calculation on Hybrid PV and Microhydro Power Plant Prototypes Based on Arduino
Hybrid Power Plant is a combination of power plants that use solar and micro hydro power sources. The purpose of this research is to measure the value of power, measure the value of current and voltage measurements using a DC voltage sensor and ACS712 current sensor. The experiment was conducted to determine the accuracy of the sensor in measuring the value of voltage and current on the hybrid prototype. In the solar panel prototype, the power obtained is 0.80332 Watt with an efficiency of 66.94%., in the micro-hydro prototype, the power is 0.02554 Watt with an efficiency of 93.89% and the hybrid prototype is 1.3564 Watt.
Study of Natural Food Sources of Proboscis Monkey (Nasalis larvatus) in the Buffer Zone of New Capital City of Indonesia
The riparian forest area along the Tunan river in Waru District, Penajam Paser Utara, is one of the proboscis monkey habitats in East Kalimantan. This area is included in the buffer zone closest to the new nation's capital city. As a result of the ongoing land use conversion, this area is divided into fragments, which have an effect on reducing the habitat. However, the presence of numerous groups of proboscis monkeys indicates that these habitat fragments can still meet their basic needs. The purpose of this study was to identify plant species used by proboscis monkey as natural food sources. Purposive sampling and observation method were used during this research. The result shows that there were 18 plant species as natural food sources, namely Avicennia marina, Elaeis guineensis, Excoecaria agalocha, Ficus benjamina, Sonneratia caseolaris, Vitex pinnata, Xylocarpus granatum, Achantus ilicifolius, Derris trifoliata, Ficus urata, Manihot esculenta, Melastoma malabathricum, Senna alata, Acrosticum aureum, Causonis trifolia, Flagellaria indica, Oxyceros longiflorus, and Loranthus sp. The hugest proportion of plant parts consumed were leaves (66.67%), while flowers and fruits were consumed in a smaller percentage. Keywords: food sources, Nasalis larvatus, proboscis monkey, riparian
Flood Vulnerability Analysis Using Ahp Method in Puwajaya Village, East Kalimantan, Indonesia
The analysis of flood-vulnerability areas in this study uses the help of a Geographic Information System (GIS) where GIS capabilities can be harmonized with remote sensing. This analysis uses five criteria, namely (1) Slope (2) Land Use (3) Distance to River (4) Rainfall (5) Rock Unit. By using three alternative approaches, Scenario 1 was analyzed with five basic criteria, Scenario 2 was analyzed with 4 basic criteria except rock units, and Scenario 3 was with 4 basic criteria except rainfall. The results of the analysis of all parameters were then compared and weighted using the Analytic Hierarchy Process (AHP) Pairwaise Comparison matrix. The weight value for scenario 1 is 0.278, scenario 2 is 0.436 and scenario 3 is 0.284. The highest scenario is scenario 2 with the weight criteria being 0.53 rainfall, 0.20 land use, 0.14 slope, and 0.13 distance to the river. From the slope analysis, the research area is in plains (at a slope level of 0-13% to 21-55%). The dominant land use in the research area are forest and ex-mining areas. The closest distance to the river is <100 meters. Rainfall analysis using the Ishoyet method resulted in the distribution of rainfall <13.6 mm which was included in the low category. All analysis results are combined using the Overlay Intersection method in ArcGIS 10.4 to produce a map of flood-vulnerability areas based on the 4 criteria used. It was found that 5% of the research sites is very vulnerable to flood, 25% of the research sites is vulnerable to flood and 10% of the research sites is endangered to flood. Keywords: Flood, Geographic Information System (GIS), Analytical Hierarchy Process (AHP), ArcGIS
The Evaluation of Pheromone Traps Glue Formula for Monitoring of Spodoptera exigua Hubner (Lepidoptera Noctuidae) in Shallot Fields
Spodoptera exigua is considered as one of the most important pests in shallot plant. The objective of the research was to evaluate activity of synthetic pheromone which diluted in glue (glue formulation) for monitoring the Spodoptera exigua moth populations. This research was conducted from November until December 2021 in Tanah Datar, Bukittinggi Regency, West Sumatera. A sex pheromone glue formula was spread on yellow board trap and applied on shallot at 14 days after planting. This research was done using a randomized design, consist of sex pheromone glue formula treatments, with different amount of active components of adhesive glue (in 100 mL) i.e. A (50 µg), B (100 µg), C (200 µg), D (300 µg), and one trap without sex pheromone as control (E). Each treatment was repeated five times. The observation was made by counting the number of moths caught in the sex pheromone trap. The results showed that an effective sex pheromone formula to attract male moths was the B formula. The B (100 µg) formula can catch more male moths higher than that of other formulas and recommended further to utilize for monitoring of S. exigua.
Caribi Mobile Application Business Process Modeling
The industrial revolution 4.0 does not only have an impact on changes in technological culture in the fields of industry, agriculture and animal husbandry also have a significant impact. The application of technology in the field of animal husbandry can assist farmers in maximizing the results of their livestock so that they get a better income and raise the standard of living of farmers. Livestock investment in Indonesia itself has become a culture with management still carried out conventionally, although some of the livestock sales processes have adapted to the use of social media for digital marketing, but not only digital marketing but the investment process needs to be digitized. Based on this, we need a technology that can provide facilities to meet the needs of the community in investing and transactions that are in accordance with the needs of end users, namely investors, breeders and buyers. So it is necessary to design the system developed to suit the needs of the user so that the user does not need to change behavior in using the application. User Centered Design (UCD) is a method in UI/UX design with a focus on user needs. UCD is part of the CARIBI Mobile App investment application software development system which was built to facilitate the digitization of investment and livestock trading transactions. The results of the UI/UX design produce 8 main needs, namely the main dashboard page, investment dashboard, login, livestock dashboard, complaints, reviews, wishlists and transactions. The evaluation carried out at the beginning and at the end uses a usability scale system with an average SUS score of >80% with an excellent rating, which means that the appearance of the CARIBI Mobile App application meets customer needs or is good.
The Effect of L-Ascorbic Acid-2-Phosphate on Human Adipose-Derived Stem Cells Population Doubling Time and Angiogenic Potency
Adipose-derived stem cells (ADSCs) have been developed as substitute cells for tissue engineering. However, in order to get a high number of cells, over-repassage leads the cells to become big in spread size indicating that senescence occurred. This study aimed to evaluate the potency of ascorbic acid to induce the proliferation and angiogenic potency of human ADSCs and inhibit the aging process of the cells. Human ADSCs were isolated by an enzymatic process. ADSCs were cultured in 10% fetal bovine serum (FBS) supplemented by ascorbic acid in various concentrations (1, 3, 6 µg/ml). The morphology, proliferation, population doubling time (PDT), and angiogenic potency were evaluated. Angiogenic potency analysis was performed using gene expression of vascular endothelial growth factor (VEGF) and its receptor (VEGFR). Ascorbic acid on 6 µg/mL suppressed the senescence proved by cell spread areas, growth curves, viability, PDT, and percentage of scratch width closure. No significant difference in vascular endothelial growth factor and its receptor expression to the control. However, the high concentration of ascorbic acid (6 µg/ml) expressed the highest VEGF and VEGFR. Our study showed that ADSCs with supplementation of ascorbic acid (6 µg/ml) promoted proliferation and angiogenic potency.