bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the effects of operating time and sediment minerals on hydro abrasive erosion in Pelton turbine
Authors: Arora N , Kumar A , Singal S K
Published: December 2024

Hydro-abrasive erosion in the Pelton turbines is attributed to high jet velocity generated by high head and abrasive sediment particles in sediment laden flow. This study presents a part of the research study that focuses on investigating the effect of sediment minerals on hydro abrasive erosion in Pelton buckets. Experiments were conducted on a Pelton jet test rig with a Pelton runner of 10 kW equipped with 20 buckets of different material using four sediment minerals (muscovite, feldspar, garnet, and quartz), operating time (3 h, 6 h, 9 h, 12 h), erosion velocity (46.58 m/s), suspended sediment concentration (1500 mg/l), and sediment size range (90-150 μm). It was found that erosion increases with an increase in the operating time; however, the rate of erosion varies with the material. Among all the materials tested, 13Cr4Ni with WC-Co-Cr coating performed best under the action of sediment and offered the best resistance to erosion. The correlations between normalized erosion and operating time were developed for each bucket material corresponding to muscovite, feldspar, garnet, and quartz sediments, and the obtained exponents of operating time vary from 0.95 to 1.22.
Mitigation of high load flow instabilities using axial water jet injection in Francis turbines
Authors: Khullar Subodh , Singh Krishna M , Gandhi Bhupendra K
Published: December 2024

The high load (HL) operations in Francis turbines lead to the inception of unsteady phenomena causing pressure pulsations, vibrations, and cavitation. The flow instabilities at HL differ from that of part load operation (PL). At high load, an axisymmetric vortical structure, rotating opposite to the runner develops in the draft tube. The authors had previously successfully employed axial water jet injection in the draft tube to mitigate flow instabilities at different part loads. The present numerical work is performed to investigate the effect of water jet injection on flow instabilities at a high-load operating condition. The simulations are performed on a model Francis turbine unit installed at IIT Roorkee. The study presents changes in the velocity and pressure distribution along with turbine characteristics, such as efficiency, and pressure recovery with the water jet injection.
Numerical Analysis of Cavitation Characteristics of Francis Turbine at Different Runner Blade Numbers
Authors: Kumar Prashant , Singal S K , Gohil Pankaj P
Published: December 2024

The main objective of this study is to evaluate the hydraulic performance and cavitation characteristics of Francis turbine at different operating conditions by varying the number of runner blades 13, 15, and 17 using commercially available CFX code. The runner blade numbers have a significant impact on both the turbine’s hydraulic efficiency and cavitation characteristic performance. The turbine efficiency and cavitation characteristic of turbine has been analysed under the best efficiency point (BEP) condition in order to achieve the optimum number of runner blades for Francis turbine. The turbulent nature of water flow through the turbine passages is accurately captured by SST turbulent model. The numerical results obtained from the CFD analysis were validated by comparing them with turbine manufacturer data available in the literature. Based on the simulation results, the hydraulic efficiency of turbine has been found to be maximum with 15 runner blades as compared to 13 and 17 runner blades. However, the predicted zone of water vapour volume fraction becomes less on trailing edge suction side of blades with an increase in number of runner blades. The results of the suggested research could prove highly valuable to hydro turbine manufacturers.
Developing a customized laboratory setup to assess sensors for real-time suspended sediment monitoring
Authors: Friz Carolin , Felix David , Evers Frederic M , Boes Robert M
Published: December 2024

Sedimentation challenges water reservoir operations globally, particularly for storage hydropower plants (HPPs), necessitating effective management strategies. One such strategy, fine sediment venting through turbines, though effective in managing sediment continuity, increases hydro-abrasive erosion on turbines due to the additional sediment load. Hence, there is a need for precise real-time monitoring of suspended sediments. Existing systems, however, often lack the capability to measure suspended sediment mass concentration (SSC) and particle size distribution (PSD) with low uncertainty, particularly for coarser particles, such as sand. To maintain particles with sizes up to 2 mm in suspension, which is the size of particles vented through the power waterways of the turbines, this study developed a customized laboratory setup with an upward flow column and a closed pump circuit. To foster a homogeneous SSC distribution, the setup was hydraulically optimized by different diffusor designs at the inlet of the upward flow column. We tested particles ranging from 1500 - 2000 μm at SSCs up to 20 gl−1 with optical and acoustic sensors to prove our concept. First results yielded as expected mostly linear relationships between instrument outputs and nominal SSC, particularly for larger particles. This indicates that the setup allows keeping particles up to 2 mm in suspension, enabling further measurement series to better understand the impacts of sand particles in combination with silt on sensor performance. This is crucial for enhancing suspended sediment monitoring capabilities for fine sediment venting at HPPs.
On the Generation of Large-Scale Vortical Flow Structures in Pipe Multifurcations
Authors: Semlitsch Bernhard
Published: December 2024

In many hydraulic power plants, the water supplied through the penstock needs to be distributed to multiple turbines. The application of pipe multifurcations is motivated by economic and efficiency reasoning. However, flow instabilities and large-scale vortical flow structures can occur for some operating conditions, causing high-amplitude pressure and mass flow rate fluctuations. To enhance the understanding of the flow instability inception, we investigate the unsteady flow in a pipe multifurcation with six branches for different operating conditions. The unsteady flow is simulated employing the large eddy simulation approach, where the numerical mesh is constructed such that y
+ < 1 and a recycling-type boundary condition is utilised to provide the turbulent inflow conditions. While the general flow pattern are described by the time-averaged results, the work focuses on analysing the unsteady physical phenomena occurring in the pipe multifurcation. At part-load operation, the results clearly show the formation of large-scale vortical flow structures stretching into the active branches. The vortices are observed to move around and eventually burst. When one vortex breaks down, the other large-scale vortices reaching into the other active branches are likely to burst and the flow pattern changes. Such events come with decreased turbulence intensity propagating through the branch line, flow separation at the branch line junction, and mass flow rate fluctuations. After a short time, large-scale vortices were established again.
Achieving zero liquid discharge through water recycle in Muara Karang Combine Cycle Power Plant
Authors: Putra S A , Yasin T R , Hikmat P J
Published: December 2024

The study evaluates a water recycling program implemented at the Muara Karang Power Plant (MKPP), which plays a crucial role in reducing wastewater and enhancing the operational efficiency of the power plant. Water is an essential resource in power generation, but its quality has been declining over time, impacting plant performance. Regular checks on the boiler water at MKPP reveal that the plant collects around 1-1.4 m3/second, which was traditionally discarded after inspection. However, considering the quality and quantity of this water, the study explores its potential for recycling. Since 2023, approximately 2,741.46 m3 of water has been reused, improving efficiency by 160 m3 per month while reducing wastewater discharge. The program demonstrates that simple yet strategic water management interventions can significantly improve operational efficiency and environmental sustainability in power plants. By recycling boiler water within the system, the plant conserves valuable water resources and lowers pollution levels. This study introduces a pioneering approach to water recycling in power plant by utilizing boiler water that was previously discarded. This innovative approach not only reduces the environmental impact but also sets a new benchmark for sustainable water management in the energy sector, providing a model for other power plants to follow.
Noise intensity analysis of building construction projects: a case study
Authors: Hatmoko J U D , Yuwono A A , Pradana R Y A , Kistiani F
Published: December 2024

Construction projects come with a variety of equipment that produce a variety of noise levels, this equipment has the potential to produce high noise levels that can impact people’s health in various ways. These effects include damage to the sense of hearing both temporarily and permanently, communication disorders, and physiological impacts. This study aims to analyze construction project noise involving construction equipment. This study identifies and classifies construction equipment that produces noise with a total of 16 pieces of construction equipment; 2 with high noise intensity; 5 with medium noise intensity; 9 with low noise intensity. The analysis used the calculation of the average noise intensity level normalized to 8 hours (Lex) so that finally a uniform classification can be made. In addition, this study also develops a plan for noise mitigation and control methods of noise that exceed the threshold value.
Indoor air quality in the university classroom: An experiment and simulation analysis in a tropical climate
Authors: Anugerah D R D , Sari D P , Harsritanto B I R
Published: December 2024

A comfortable classroom environment depends heavily on indoor air quality to maximise productivity and performance. This statement refers to the preliminary survey indicating that most university students spend 90% of their time inside buildings. Each day, between three and six hours are spent in the classroom. However, most classrooms today are equipped with AC units, which restrict air exchange. A major reason is the high temperatures, especially in tropical climates. Overly high CO2 concentrations will have a negative effect on health. The purpose of this research is to identify the indoor air quality of Classroom A.202, Department of Architecture, Diponegoro University, focusing particularly on CO2 concentrations. A combination of experiments and simulations is used in the method. For 10 minutes, an Air Quality Monitor and CONTAM simulation software were used to measure and simulate window openings and occupant movements. The results show that CO2 concentration levels increase as occupants in a room increase and air circulation becomes obstructed. It was found that good air circulation can lower CO2 levels, resulting in an optimal learning environment.
Charting the currents of environmental concern: a decades-spanning scientometric analysis of riverine debris
Authors: Sani M T , Budihardjo M A , Sarminingsih A
Published: December 2024

Debris in water bodies, particularly rivers, is a major environmental concern, with Southeast Asia contributing around a third of global debris pollution in 2015. This debris poses severe ecological risks, including entanglement and ingestion, which can lead to biodiversity loss. Despite extensive research on marine debris, there has been a lack of scientometric reviews using tools like CiteSpace to analyze riverine debris, especially in Southeast Asia. Thus, this study aims to explore research trends on riverine debris by analyzing Scopus-indexed articles from 1995 to 2024, identifying 156 relevant articles and exploring the monitoring effort. CiteSpace analysis reveals that Indonesia leads Southeast Asia in riverine debris research with 79 publications, followed by Malaysia, Thailand, and Vietnam. The studies primarily span Environmental Science, Earth and Planetary Sciences, and Agricultural and Biological Sciences. Key research has been conducted in Indonesia, Vietnam, and the Philippines, emphasizing the urgent need for improved waste management. These studies focus on debris composition, the effects of increased plastic use during the COVID-19 pandemic, and future waste projections, underscoring the need for targeted interventions to address environmental impact.
Critical review of jatibarang reservoir management in semarang city: an institutional perspective
Authors: Margono A B , Hadi S P. , Hidayat J W
Published: December 2024

This review critically examines the management of Jatibarang Reservoir in Semarang City from an institutional perspective, highlighting key challenges and proposing strategic improvements. The reservoir plays a vital role in water supply, flood control, and environmental enhancement, yet faces significant issues such as sedimentation, erosion, policy fragmentation, and inadequate institutional coordination. Through an analysis of global best practices and innovative management strategies, this review underscores the importance of robust institutional frameworks, stakeholder collaboration, and advanced technologies in enhancing reservoir management. Recommendations include the establishment of a centralized authority for better coordination, the integration of community and private sector efforts, and the adoption advanced sediment management techniques. These measures are critical for ensuring the sustainability of Jatibarang Reservoir and contribute to broader Sustainable Development Goals (SDGs) in urban water management.
The utilization of exopolysaccharide (EPS) from microalgae Chlorella vulgaris in microplastic removal
Authors: Joelyna F A , Hadiyanto  , Khoironi A , Pratama W D
Published: December 2024

The most common plastic kinds detected in aquatic systems are polypropylene (PP) and polyethylene terephthalate (PET), which are the microplastics employed in this investigation. This study aims to determine the ability of microalgae to remove microplastics. Because they contain chemicals and additives, microplastics have an influence on microalgae growth. Exopolysaccharide (EPS), an extracellular molecule, is produced by Chlorella vulgaris. Exopolysaccharide (EPS) is used in the hetero-aggregation process to generate flocs, which facilitates the removal of microplastic. Both internal and external factors influence the production of microalgal EPS. The interaction between microplastics and microalgae, used at 1000 mg/L, is one of the external influences. Every two days, the optical density (OD) of microalgae is measured to determine the growth rate of Chlorella vulgaris. We calculated and determined the dissolved EPS gravimetrically as dry EPS (mg/ml). Flocs were created as a result of the hetero-aggregation of microplastics, EPS, and Chlorella vulgaris. The documentation of floc formation and EPS weight shows that the polyethylene terephthalate (PET) microplastic type removed the most microplastics using exopolysaccharide. The dry weight of the exopolysaccharide (EPS) Chlorella vulgaris control was 735 mg/L, the polypropylene (PP) treatment was 835 mg/mL, and the polyethylene terephthalate treatment was 1034 mg/mL.
Centralized Automatic Greasing with Intelligent Notification to Maximize Reliability and Hazardous Waste Reduction in Combined Cycle Power Plant
Authors: Kurniawan A , Danaputra F I , Putra P D , Fatimah F , Rahmanissa A
Published: December 2024

Cooling water system on Steam Turbine Generator is affected by sea water cleanliness. Traveling Drum Screen (TDS) is used to filter trash and rubbish from the sea water before entering cooling water system in a Power plant. From 2018 to 2022, the Pinion Gear on the Traveling Drum Screen had been damaged many times with an average of 6 times per year and had potential loss of IDR 2.8 billion. From the inspection results, damage occurred on support bearing due to uneven lubrication entering the bearing housing. The lubrication process was conducted manually and produced hazardous waste. This study aims to analyse how to change the system to become digitally maintain and produce less waste. The systematic methodology and implementation of the new system will be explained on this article. The method of this study can increase the optimization of the greasing system and TDS reliability by 2.43×10−3. It also cuts corrective maintenance out. The application of the changed system impact to minimize manual action work and usage of absorbent pad. The results of this research are reducing contaminated hazardous waste and saving hazardous waste management cost.
Promoting green-pesantren and circular economy; Improving santri’s knowledge on food waste management and maggot cultivation
Authors: Nurkhin A , Martono S , Fachrurrozie F , Mukhibad H , Rohman A , Prabowo W T J , Rofiq A
Published: December 2024

The issue of green-pesantren or eco-pesantren is increasingly important to be realized by pondok pesantren by managing the pesantren environment to be cleaner and greener and increasing the knowledge of santri (student) in environmental issues, including in waste management. This research aims to test the effectiveness of waste management and maggot cultivation education and training on santri’s knowledge. An experimental research model is used to analyze the impact of the treatment given, namely education and training for santri. The data collection methods used were tests and observations. The data analysis method used is descriptive statistics and t-tests. The research was conducted at Pondok Pesantren As Salafy Al Asror Semarang, involving 30 santri in May 2024. The study results showed that santri’s knowledge in managing food waste and cultivating maggots still needed to be higher. The education and training significantly increased students’ knowledge of food waste management and maggot cultivation. Students are expected to be able to follow up on the training provided by carrying out maggot cultivation in the pondok pesantren environment or respective places of residence.
Biodegradation of polyethylene terephthalate (PET) plastics using a combination of Aspergillus niger and Trichoderma harzianum
Authors: Tegariyanto M R , Titah H S , Pratikno H
Published: December 2024

Plastic is a synthetic organic polymer widely used across various industries, yet its waste contributes significantly to environmental pollution. Polyethylene terephthalate (PET) is one of the most common types of plastic, known for its resistance to degradation, which poses significant environmental risks. This study aimed to evaluate the biodegradation potential of a combination of Aspergillus niger and Trichoderma harzianum fungi on PET. The fungi were isolated using potato dextrose agar (PDA) and incubated in potato dextrose broth (PDB) to establish growth curves and prepare inocula. PET samples were sterilized and subjected to biodegradation tests in minimal salt medium (MSM) with 10% and 15% fungal inoculations over 30 days. The results revealed significant physical alterations in PET, including color changes, surface curvature, and scratches. Weight loss measurements indicated that the combination of A. niger and T. harzianum achieved 1.80% degradation with 10% inoculation and 1.13% with 15% inoculation. Furthermore, Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated significant changes in functional groups, including the formation of new hydroxyl, carboxylic acid, and alkene groups, indicating polymer chain breakdown. This study highlights the novel application of fungal consortia in PET biodegradation and underscores its potential as a sustainable approach for managing PET plastic waste.
Analysis of soil bearing capacity to determine foundation design in Ngawi City, Indonesia
Authors: Widiarso DA , Huda LN , Trisnawati D , Hidayatillah AS , Adibah NN
Published: December 2024

Improving economic value in a region can be achieved through planned infrastructure support. As one of the biggest shopping centers, Ngawi Big Market has revitalization activity. Before beginning the revitalization process, it is crucial to test the ability of soil to withstand the load, which is called the soil bearing capacity. In the process of this research, the analysis was carried out by evaluating geological and geotechnical conditions, and calculations of soil bearing capacity values. Analysis of soil bearing capacity value was using NSPT data which uses the equation from Luciano Decourt along data from laboratory tests. The lithology of the research area consists of siltstone, and the drilling results consist of silt, fine sand and clay. The land area of Ngawi Big Market is 15,000m2 with the building area of the previous market being 14,500m2. The permitted lowest bearing capacity is at point BH-T3, namely 6.7 tons at a depth of 2.0 meters, while the highest is at point BH-T1, namely 380.3 tons at a depth of 20.00 meters. Based on the results of the analysis, Ngawi Big Market’s revitalization project recommended to carry out the geotechnical engineering to strengthen the soil as well as detailed calculations of building loads so that they do not exceed the permitted bearing capacity.
The effect of fenton oxidation on the quality of pharmaceutical industry wastewater: a case study of bod, cod, toc, and turbidity parameters
Authors: Zaman B , Hardyanti N , Pramesti I A , William G S
Published: December 2024

Chemical residues from pharmaceutical manufacturing processes possess the potential to pollute the environment, particularly the aquatic ecosystem. Environmental indicators include COD, BOD, TOC, and turbidity levels that exceed limits set by regulations. This research is focused on investigating fluctuations in the quantities of wastewater contaminant parameters from pharmaceutical manufacturing facilities before and after treatment with the fenton oxidation method, as well as examining the effectiveness of the fenton oxidation process on water quality using predetermined parameters. This study involves independent variables that included various dosages of Fe2+ and H2O2. Adjusting the pH of the water after stirring to 7 stimulates the flocculation process, which effectively eliminates contaminants, specifically variant 15g FeSO4 and 100 ml H2O2 which successfully lowers turbidity by 99.55%, reduces BOD by 60%, COD removal by 98.69%, and reduces TOC by 92.94%. Control variables include initial contaminant amount, pH, temperature and pressure, fenton oxidation process duration, and instrument conditions.
Analysis of domestic waste generation in one of residential areas on Srondol Wetan Sub-districts, Banyumanik District, Semarang City
Authors: Nugraha W D , Samadikun B P , Damanik E Y , Salsabila G F D , Fikriana H K
Published: December 2024

The more densely populated an area is, the greater the waste produced. One of the residential areas in the Banyumanik District, Semarang City with a relatively high population density is in RW 07 Srondol Wetan Sub-district. Therefore, a study was conducted to determine the amount of waste generated, the volume, and the composition in RW 07 Srondol Wetan Sub-district by implementing waste sampling that refers to SNI 19-3964-1994. Other data collection was carried out by observing and conducting surveys. The samples range from low, middle, to high-income housing. Based on the result, the weight of waste generation in RW 07 Srondol Wetan Sub-district is 0.2836 kg/person/day, and the volume of waste generation is 2.9333 liter/person/day. The composition of the waste generated consists of 61.90% food waste, 11.63% plastic, 6.41% paper or cardboard, 12.26% leaves and wood, 0.93% fabric, 0.37% metal, 0.42% glass, 0.02% rubber, and 6.06% other waste. Based on observations and interviews, most of the waste is collected and transported by collectors and then disposed of directly to the nearest TPS. Meanwhile, waste sorting is only carried out on organic waste and only a few residents process waste using the composting method. Some residents have already done waste management in the form of collecting and selling valuable waste, which is a good indication of the need for a waste bank in the area.
Mitigating membrane fouling in potable water supply by employing the ozonation process
Authors: Istirokhatun T , Susanto H , Andarani P , Sarminingsih A , Filardli A M I
Published: December 2024

Dealing with membrane fouling poses multiple difficulties. Conventional cleaning techniques, such as backwashing and chemical cleaning, are frequently inadequate in effectively dealing with various types of fouling and can result in the gradual deterioration of the membrane. Advanced technologies such as ozone treatment and advanced oxidation processes present interesting answers, but they necessitate meticulous optimisation and can incur significant costs. It is crucial to develop membrane materials that are resistant to fouling and to create monitoring and control systems that operate in real-time in order to enhance fouling management. It is essential to overcome these problems in order to improve the performance, cost-effectiveness, and sustainability of membrane-based water treatment systems used in the production of drinking water. This paper overviews the role of ozonation when it is coupled with membrane process. In general, ozonation as pretreatment and/or post treatment and its mechanism in fouling mitigation, investigation of elimination mechanism of natural organic matter (NOM) and bio-toxicity in the ozonation process, and the prospect of ozonation to be used in fouling mitigation of membrane process for potable water reuse.
The effect of additive compound in self-compacting geopolymer mortar on the compressive and flexural strength
Authors: Hidayat B A , Indriyantho B R , Purwanto  , Prasetya B H , Priastiwi Y A , Pratama R , Anjani B R
Published: December 2024

Using geopolymer materials in concrete manufacturing has been found to lead to inconsistent and variable quality, mostly because of its low workability. Further research was undertaken to improve the workability of self-compacting geopolymers by additional examination. This study aims to assess the influence of different additives on the mechanical properties of self-compacting geopolymer concrete, specifically in relation to its compressive and flexural strength. The compressive and flexural strength of geopolymer mortar was assessed after 28 days of curing, during which it was covered with a thin film layer. Cube and beam specimens were used for testing. The findings suggest that the inclusion of additives in the geopolymer mortar yields compressive strength similar to that of conventional mortar, except in cases when extra water is introduced, leading to a decrease in compressive strength compared to traditional mortar. Moreover, the use of additional cement results in a 1.29-fold enhancement in flexural strength when compared to geopolymer mortar.
Geological Condition Characterization and Coal Resource Estimation at the “KJG” Pit of PT Bukit Asam Tbk, Muara Enim Regency, South Sumatra Province
Authors: Pangestu A R , Adni A , Fahrudin  , Qadaryati N , Zulkarnain D A
Published: December 2024

Coal is a conventional energy source found in tropical countries (e.g., Indonesia) with varying distribution and thickness in the South Sumatra Basin. However, the thickness of the coal seams was not evenly distributed. This affected the estimation of coal resources in the mining area of PT Bukit Asam Tbk in Tanjung Enim, Muara Enim Regency. We used field observation methods and borehole data analysis to determine the geological conditions and estimate the coal resources. The geological condition seems to indicate a claystone unit with tuffaceous sandstone interbeds and a sandstone unit with claystone interbeds. These two units might host coal seams (i.e., A1, A2, B1, B2, and C), where the coal seam thickness may determine increased towards the south and west in the study area. The coal resource estimation based on the SNI 5015: 2019 classification, under moderate geological conditions, can result in a total of 26.034.991 tonnes of measured resources, 25.209.688 tonnes of indicated resources, and 11.189.554 tonnes of inferred resources. Therefore, to ensure efficient coal mining in accordance with the measured reserves, the stripmining method may be used by the company.
Optimizing green building practices: a case study in psychology building of universitas diponegoro in semarang, indonesia
Authors: Nindita Velma , Purwanto Purwanto , Windarta Jaka , Setyowati Erni
Published: December 2024

Buildings have a significant impact on environmental deterioration and climate change. It is crucial to design ecologically friendly and energy-efficient buildings to reduce these effects. Green construction concepts place high importance on using resources efficiently, minimizing waste emissions, and using sustainable materials over the whole lifespan of a structure. The building envelope, which includes walls, doors, windows, floors, and roofs, plays a crucial role in energy-efficient design. This study aims to achieve green building certification for the Universitas Diponegoro (UNDIP) Psychology campus by examining heat transmission, adherence to local green building rules, and energy consumption in current building designs. The study assessed the campus using SketchUp software for design, an overall thermal transfer value (OTTV) calculator, and EDGE (Excellence in Design for Greater Efficiencies) software for analysis. The analysis showed that the OTTV value was 27.58 watts/m2 and the ultimate energy consumption was 41,028.43 kWh/month.

The findings suggest that the campus is following Semarang Mayor’s regulation No. 24 of 2019 and is regarded to be ecologically friendly. Optimization of EDGE design solutions for energy analysis resulted in energy efficiency of 60.6%. The study presents alternative architectural plans that fulfill the requirements of green building standards, providing valuable information on techniques for renovating existing structures.
Climate change adaptation strategy of agricultural sector in Southeast Asia
Authors: Nurjati Eka , Adityawati Septian
Published: December 2024

Tropical regions such as Southeast Asia are more vulnerable to food insecurity because climate change causes disruptions in the food supply chain. An extreme increase in the population exacerbates this condition. Southeast Asia also often experiences extreme weather, adversely affecting the farmers’ livelihood. Climate change that has occurred for decades has forced smallholder farmers to adapt. This study aims to identify the impact of climate change and adaptation strategies of smallholder farmers and other Southeast Asian stakeholders. The methods used in this study are bibliometric analysis and systematic literature review (SLR). The result explains that climate change significantly impacts the decline in agricultural productivity, food nutrition, environmental quality, and resource instability. Climate change has also contributed to the increase in poverty. The adaptation strategies at the upstream level include sustainable agricultural practices, agroforestry, circular economy, crop-livestock integration, forest recovery, environmentally-friendly technology, changes in sowing and planting dates, traditional water irrigation practices, and smart farming. At the downstream level, many rural farmers migrate to cities because they cannot continue farming. The government has implemented social protection and climate risk insurance schemes for farmer households at the downstream level.
Application of Waste Bioconversion Technology Palm Oil Solid Waste in Order to Realizing Circular Economy Economy of Oil Palm Plantations in Subulussalam City Subulussalam: Case Study of PT. Samudera Sawit Nabati Subulussalam City
Authors: Miswardin  , Deli Anwar , Mariana
Published: December 2024

Oil palm (Elaeis guineensis), produces the most widely produced and used vegetable oil in the world. In addition to its many benefits, the volume of solid waste of TKKS per production also continues to increase. The production of solid waste per hour reaches 6.9 tons per day as much as 41.4 tons and continues to increase every time. Solid waste that accumulates has an impact on the environment and health, but when converted it can produce benefits, one of which is a medium for breeding BSF larvae eggs which later produce maggot as high-protein animal feed, this can also realize a circular economy. The purpose of this study was to determine the application of bioconversion technology of TKKS solid waste in realizing a circular economy. This research applies the experimental method, starting with the hatching of larval eggs until they are ready to be used as animal feed. Then analyzed production costs, benefits, and financial analysis in the form of narratives and tables. The results of the research have been obtained, there are two steps as an effort to minimize the solid waste of TKKS which lasts from 2016 to 2024. During this time, TKKS is only used as compost and burned. Financially, the utilization of solid waste through bioconversion technology can produce animal feed with a selling price of Rp. 10,000-Rp. 15,000 per kilogram of maggot and produce kasgot (fertilizer) reaching 90% with a selling price of around Rp. 10,000 per kilogram.
Feasibility study of processing wood twig waste into liquid smoke at the integrated waste management facility Diponegoro University
Authors: Azzahra F , Yusuf A B , Wicaksono P A , Sari D P
Published: December 2024

The pruning of trees along the road which is carried out every day by Diponegoro University causes piles of wood twig waste. There is no processing system for this waste. On the other hand, wood-waste can be processed into liquid smoke. Liquid smoke produced from processed wood-waste will not leave a coconut taste like liquid smoke in general and has a more distinctive and smokier aroma when it is used. This research aims to assess the market, technical and financial feasibility of processing wood twig waste into liquid smoke at the integrated waste management facility of Diponegoro University. Market feasibility was considered through Segmenting, Targeting and Positioning (STP) framework and marketing mix-4P. Technical feasibility was considered through calculating the availability of raw materials, production capacity and facility requirements. Financial feasibility was considered using the Net Present Value (NPV), Internal Rate of Return (IRR), Payback Period (PP), and Profitability Index (PI) methods. The results indicate that, provided at least 80% of the produced output is successfully sold at a price of IDR 35,000 per liter, the investment in processing wood twig waste into liquid smoke is considered feasible from market, technical, and financial perspectives.
Legal protection of coastal areas and surrounding communities affected by shrimp pond waste (case study: Beting Beach, Bintet Village)
Authors: Puspitasari D , Jannah M , Sari L , Manik J D N
Published: December 2024

Waste pollution from shrimp farming activities in the Beting Beach area of Bintet Village has created a situation of serious concern for the marine ecosystem and the surrounding community. This study aims to determine the impact of shrimp farming activities and the form of legal protection. This research uses empirical juridical method with qualitative approach. The results showed that the impact caused in the form of water pollution, namely changes in the color of water accompanied by foul odors and air pollution that disrupts the social activities of the community. Legal protection for coastal areas that have been polluted by waste must be carried out by taking firm action against shrimp farming businesses and restoring affected areas through Law Number 32 of 2009 addressing Protection and Management among the Environment. The community’s legal protection is governed by One of the laws of 2014 involving Amandements to Law Number 27 of 2007 surrounding Administration of Small Islands and Coastal Areas. The statute in question states that administrative sanctions, such as written warnings, temporary site closure, license revocatiobs, and\or administrative fines, are imposed in the event of a violation pertaining regarding the accepting of location and management permits.
Design and modelling of fastener system on sand core making shell machine
Authors: Suganda W , Purwanto H , Syafa’at I , Dzulfikar M
Published: December 2024

Sand core making shell have been considered as a system for metal casting. In the molding of molten casting, the shell machine needs to be fasten using bolts and nuts. The concept of the article discusses bolt’s strength using analytical methods and numerical calculations of materials and dimensional variations. The size and load received by the mold on the automatic sand casting machine normally 1000 kPa. Sand casting mold have dimension around 470 × 415 × 550 mm. Thus, the proposed clamped by 4 hardened hexagonal bolts. Our study provides understanding for the design and numerical modelling of fastener system for the mold clamping of metal casting.
The effect of adding fly ash on the shear strength of clay soil considering the age of fly ash
Authors: Kusniadi W , Apriyanti Y , Sandy B D A
Published: December 2024

The Clay soils present specific challenges in civil engineering due to their inherent weaknesses. Therefore, it is crucial to enhance bearing capacity of clay soil through stabilization methods such as chemical stabilization using fly ash. This research investigates the effect of fly ash at varying ages as stabilizing agent for clay soil on shear strength. In this research fly ash was added in proportions of 8%, 16%, and 24% by weight of dry soil, using both fly ash aged less than 1 year and fly ash aged more than 1 year. The clay soil used in this research was classified using Unified Soil Classification System (USCS). Shear strength tests were conducted in accordance with Indonesian National Standard (SNI) procedures. The results showed that fly ash aged more than 1 year consistently improves shear strength of the clay soil with increasing fly ash content, with the highest shear strength on 53.089 kN/m2 observed in the mixture of clay soil and 24% fly ash aged more than 1 year. While, for fly ash aged less than 1 year the maximum shear strength on 34.962 kN/m2 was achieved with 16% fly ash, then the strength decreased to 32.372 kN/m2 with 24% fly ash.
Isotope method for uncover characteristics and recharge areas of groundwater in Pangkalpinang City, Bangka Belitung Islands Province
Authors: Yulita R , Putra D P E , Baskoro W A
Published: December 2024

Groundwater recharge areas have an important role in water resources management, especially in maintaining the sustainability of groundwater in terms of quantity and quality. However, groundwater recharge areas whose water is utilized as one of the sources of clean water for the people of Pangkalpinang City have never been studied before. Based on these problems, this study was conducted with the aim of knowing the groundwater recharge area and the isotope characteristics of groundwater utilized by the community in Pangkalpinang City. 3 rainwater samples, 1 spring sample, 5 groundwater samples from dug wells, and 8 groundwater samples from drilled wells were taken directly and analyzed for 2H and 18O isotope content. The analysis results showed that rainwater 2H values are -2,40/00—8,0 9 0/00 and 18O -9,7 40/00—52,8 5 0/00. Spring water has values 2H -8,090/00, 18O -42,240/00. Borehole water has 2H values of 5,8 6 0/00—7,3 2 0/00 and 18O -35,9 2 0/00—45,2 80/00. They dug well water that has values of 2H 3,80/00—6,830/00 and 18O-24,8 5 0/00—41,7 80/00. The results of rainwater data plotting show that springwater, dug well, and drilled well water enters the hydrological cycle or meteoric water. For spring water, borehole water and some dug well water interact with each other and are not affected by evaporation. They are in the same aquifer system or may tend to come from the same source. Still, there is 1 dug well (SG-52) that moves away from the meteoric water trendline, so it can be interpreted that the well water evaporated during the journey from the recharge area. The groundwater recharge area in the study site is located at elevation 67,68-204 masl or outside of the study site, and the groundwater recharge area is most likely along the south to northwest side of the study area.
Optimizing the C/N ratio in composting fresh coconut husk and shell waste for organic fertilizer production
Authors: Tran T , Thi Q V C , Duong D V , Trung L D , Trang N T Q , Hong L T A
Published: December 2024

The Mekong Delta region produces significant organic by-products from agriculture, which can cause environmental pollution and infectious diseases. However, these by-products can be recycled into valuable raw materials for organic fertilizers. This study aims to create an organic substrate from fresh coconut husks and waste shells, reducing waste and maximizing the value of these materials. By determining the nutritional properties of shells and coconut husks, the study calculates the optimal mixing ratio with substrates and additional fertilizers to achieve a suitable C/N ratio for composting. The decomposition process is monitored over 45 days, tracking pH, temperature, total aerobic microorganisms, cellulose-decomposing microorganisms, and pathogenic E. coli - Coliform. Post-decomposition, the treatments are evaluated for organic matter content, total nitrogen, and phosphorus, and compared with the organic fertilizer standard QCVN 01 - 189:2019/BNNPTNT. Preliminary results show effective decomposition from day 6, with temperatures exceeding 50°C. Most final compost samples meet quality standards for organic and microbial fertilizers and show promising results in mustard greens trials. Thus, the fresh coconut husk and shell powder mixture has the potential to produce optimal compost, effectively recycling these materials.
Analysis of land use using Landsat 8 OLI in coastal North Sumatra: a study from 2019 to 2024
Authors: Nabiha R I , Zahra R A
Published: December 2024

Medan and Deli Serdang are recognized as the most developed regions in Northern Sumatra. However, there have been limited studies focusing on recent land use changes in their coastal zones. To address this gap, this study aims to analyze land use in Medan and Deli Serdang and examine the changes between 2019 and 2024. Using recent Landsat 8 OLI imagery, a supervised classification was conducted in Google Earth Engine. The CART classifier was used to divide the land use into water bodies, built-up, agricultural land, and mangroves. The Kappa index for 2019 and 2024 were 0.78 and 0.77, respectively, indicating reasonable classification accuracy. Agricultural land was found to be the dominant land use type, covering 52.78 % in 2019 and 51.76 % in 2024. A decrease was observed in agricultural land and water bodies, while mangrove coverage and built-up areas increased. The findings provide current conditions of land use in the coastal area of Medan and Deli Serdang, especially for planning and conservation in the coastal area.
Hydrophobic properties of phytoplankton-enhanced tapioca starch biocomposites
Authors: Setiawan Y , Ariksa J , Asriza R O , Wijianti E S , Taufiq M A
Published: December 2024

Sustainable material production from renewable resources is currently popular. This is due to the increasing awareness of the community towards the environment. Various products have been developed with natural materials to replace conventional plastics. Alternative materials to replace conventional plastics that are environmentally friendly are readily available, such as tapioca starch. Starch is a natural polymer that is very abundant and promising as a food packaging material. Starch is also easily degraded, non-toxic, and inexpensive. However, starch has bad air barrier properties, low hydrophobicity. To reduce these weaknesses, phytoplankton can be added to pure starch films. This study has succeeded in seeing the hydrophobic properties that the transmittance value for O-H stretching increased after phytoplankton was added to tapioca starch. Meanwhile, the transmittance of O-H at a wavelength of 3292 cm−1 for 0 ml of Starch/PP film was 37.28%. While the addition of phytoplankton suspension, the O-H transmittance at a wavelength of 3292 cm−1 for 20 ml of Starch/PP film was 43.67%. In this case, the addition of phytoplankton suspension increased the transmittance value from 37.38% to 43.67%. This finding indicates that well-dispersed phytoplankton in the PVA matrix form stronger hydrogen bonds, increase the hydrophobic properties of the biocomposite, and reduce the free O-H content.
Analysis of milling time effect on nanomaterial particle size using a laboratory-scale horizontal ball mill machine
Authors: Suhdi S , Saputra A , Rodiawan R
Published: December 2024

The advancement of nanotechnology has driven the need for efficient nanomaterial production methods. This research aims to analyze the effect of milling time on nanomaterial particle size using a laboratory-scale horizontal ball mill machine. The research method involved designing and constructing a horizontal ball mill machine, as well as testing using carbon powder with an initial size of 100 mesh (149 μm). Milling time variations tested were 6, 8, and 10 hours. Particle size characterization was performed using a Scanning Electron Microscope (SEM). Results showed that longer milling times produced smaller particle sizes. Milling for 6 hours resulted in an average particle size of 220.719 nm (63.13% of the sample), 8 hours produced 216.385 nm (77.01% of the sample), and 10 hours yielded 82.519 nm (86.99% of the sample). The study concludes that the designed horizontal ball mill machine can produce nanomaterials, with milling time inversely proportional to the resulting particle size. This research contributes to optimizing nanomaterial production processes using the ball mill method.
Biodegradable antibacterial plastics from porang fermented flour
Authors: Helmi H , Kusmiadi R , Karsiningsih E
Published: December 2024

Plastic is a waste that is difficult to handle and decompose. Biodegradable plastic can be solution to overcome this problem. The aim of this study is to investigate the potential of naturally fermented porang flour as a bioplastic based on the degradation process in the soil and its antibacterial properties as food packaging. The biodegradable plastics were made by mixing vinegar, food grade glycerine and porang fermented flour. The degradable test was carried out by calculating the weight of the plastic after it was buried in the ground for 14 days, the antibacterial test was carried out against bacteria, namely Escherichia coli and Staphylococcus aureus using agar diffusion with paper discs. The antibacterial ability test as a food wrapper was carried out by counting the total bacteria and total fungi after incubation of the rice wrapped in plastic for 2 and 5 days. The results showed that porang fermented flour did not have antibacterial activity. The total colony of bacteria and fungi of biodegradable plastics wrapped rice were lower than synthetic plastic. The biodegradable plastics from porang fermented flour (BPPFF) were faster degradation than synthetic plastics and D2 showed the fastest among them.