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The piping systems must fulfill the criteria of hydraulic efficiency and structural durability, particularly for elbow pipes that experience sudden direction changes resulting in secondary flows, pressure drop, and erosion risks. This paper provides a critical review of elbow geometry modifications to address the issue of pressure drop and erosion risks while placing them within a broader context of geometric flow stabilization principles. The paper not only provides an overview of curvature ratio (R/D), cross-sectional changes, connecting lengths, and modified elbow geometry configurations but also makes an attempt to link internal pipe flow behavior with the principles of aerodynamic flow stabilization used in crosswind shielding and flow control systems. In addition to this, a critical methodology discussion is provided by comparing conventional Reynolds-Averaged Navier-Stokes (RANS) equations with new trends and techniques such as the Lattice Boltzmann Method (LBM) used for simulating complex vortex flows and unsteady flow behaviors. The paper further emphasizes the need to move away from traditional single-parameter geometric modifications towards multi-objective optimization techniques that incorporate multiple constraints related to pressure drop, erosion rates, structural integrity, and manufacturability constraints. The results show that the optimization of the curvature ratios and connecting lengths of the pipes effectively reduces erosion and stabilizes the gradients, although methodological inconsistencies in the approach to turbulence modeling and validation persist. This review article synthesizes the current knowledge and introduces an integrated approach for future research and elbow pipe design.

Sustainable development has become a crucial issue and a moral obligation for all nations. However, the implementation of sustainable business practices in Indonesia, especially in the field of the tourism industry, including the Bukit Lawang tourist destination, is still weak. This encourages tourism managers to change their business model as a step towards making Bukit Lawang an international tourist destination. This can be achieved through competency development sustainable business management model. This article attempts to apply the design thinking model to creating innovative sustainable business model in tourism in the Bukit Lawang area, using qualitative research methods and design thinking procedures. The population of this study includes tourism managers and visitors in Bukit Lawang area. Sampling techniques such as stratified sampling and purposive sampling, and both primary and secondary data were collected. This article presents a framework for sustainable tourism businesses model in Bukit Lawang, which is built based on three dimensions: facilities, services and systems. This dimension serves as a key differentiator of sustainable value propositions in tourism businesses related to the three pillars of sustainability: economic, social and environmental. The focus of this framework is creating value sustainable tourism business regarding impact reduction, risk mitigation and compliance.

Improving the quality and quantity of infrastructure leading to agricultural production centers will increase the economic activities of the community. The more stable infrastructure of agricultural centers will facilitate access to the location, more competitive prices, and more guaranteed quality so that it will increase agricultural production and productivity as well as the income and welfare of the community, especially farmers. The contribution of Serdang Bedagai’s agricultural and plantation sectors is so large that it is only natural that the priority of infrastructure development is the construction of roads and bridges to facilitate the mobility of agricultural products. This study was conducted to provide additional perspectives and references on the importance of infrastructure in improving the welfare and income of rice farmers in Serdang Bedagai regency. This study employs quantitative approaches. The investigation took place within Serdang Bedagai Regency, Sumatera Utara Province by distributing questionnaires to respondents, namely 96 farmers. Respondents were farmers representing 17 sub-districts. The findings indicated that infrastructure development positively and significantly influences the income of farmers producing the main commodities in the Serdang Bedagai area. Furthermore, it is shown that road conditions (X) have an impact of 47.4% on the income (Y) of major commodity farmers in the Serdang Bedagai regency.

The management of freshwater resources of jurung fish with local wisdom in the Lau Teba River makes one of the watersheds like a pond but without using cages or other barriers. Jungle fish remain in their natural habitat in the river without being blocked by cages or other barriers. The purpose of this study was to explore and analyze the management of the freshwater fish of Jurung with the Local Wisdom approach, as well as the potential of natural resources as a tourist attraction. The form of research used in this study used a descriptive method with a qualitative approach. Data was collected using interviews and observations at the research site. The results show that the concept of natural resource management with local wisdom makes nature choose its own resources. Jurung fish managed with the concept of local wisdom will be selected through natural processes. Included in the process of taking fish using a rod, we do not choose the fish we take, but fish that are taken based on the natural selection process which is a tourist attraction.

Sago solid waste is a lignocellulosic material that can be used as a raw material for making bioethanol. The lignin component of lignocellulose can slow saccharification by preventing cellulase enzymes from accessing cellulose. The pre-treatment stage is the first stage of the lignocellulose-to-bioethanol conversion process, and it is used to lower lignin levels in lignocellulose. Saccharification and fermentation are the next processes in turning lignocellulosic material to bioethanol. The pre-treatment stage was carried out in this study using a 10% NaOH solution at a 4 bar pressure reactor and a temperature of 140 °C, while the saccharification and fermentation stages were carried out simultaneously (SSF) using cellulase enzymes and yeast Saccharomyces cerevisiae at 30 °C and pH 5. The ratio of sago solid waste to NaOH solution and the period of the pre-treatment process were varied in the study. The sago solid waste to solvent ratios were 1:5, 1:6, and 1:7, with processing times beginning at 20 minutes, 30 minutes, and 40 minutes. The maximum lignin reduction results (60.11%) were obtained at a ratio of 1:7 and a pre-treatment time of 40 minutes, while the highest yield of sago solid waste mass (35.14%) was obtained at a ratio of 1:5 and a pre-treatment process duration of 20 minutes. The results of the initial treatment stage were then continued with SSF for 0 hours, 24 hours, 48 hours, and 72 hours with the highest bioethanol content of 12% at 72 hours.

The focus of this research is to describe the effectiveness and response of students on the use of Digital Electronic Practicum with Logisim Application using Google Meet. The research subjects were 50 Physics Education Students of Lambung Mangkurat University taking the Digital Electronic course. The data of this study were collected by using practicum assessment sheets and students' response questionnaire. The results showed that the mean score of practicum results from digital electronic practicum with Logisim application using Google Meet was 70.58. Thus, the effectiveness of the implementation of the Digital Electronic Practicum with Logisim application using Google Meet is in a good category. Data from the students' response questionnaire was 3.83 in average, so it was categorized as good. Thus, it is concluded that the Digital Electronic Practicum with Logisim application using Google Meet is effective to implement and obtains a very good response from the students.

Accurate mapping of forest canopy height is essential for monitoring forest structure, assessing biodiversity, and informing sustainable management practices. However, obtaining high-resolution canopy height data across large tropical landscapes remains challenging and prohibitively expensive. While machine learning approaches like Random Forest have become standard for predicting forest attributes from remote sensing data, deep learning methods remain underexplored for canopy height mapping despite their potential advantages. To address this limitation, we developed a rapid, automatic, scalable, and cost-efficient deep learning framework that predicts tree canopy height at fine-grained resolution (30 × 30 m) across Indonesian Borneo’s tropical forests. Our approach integrates diverse remote sensing data, including Landsat-8, Sentinel-1, land cover classifications, digital elevation models, and NASA Carbon Monitoring System airborne LiDAR, along with derived vegetation indices, texture metrics, and climatic variables. This comprehensive data pipeline produced over 300 features from approximately 2 million observations across Bornean forests. Using LiDAR-derived canopy height measurements from ~100,000 ha as training data, we systematically compared multiple machine learning approaches and found that our neural network model achieved canopy height predictions with R2 of 0.82 and RMSE of 4.98 m, substantially outperforming traditional machine learning approaches such as Random Forest (R2 of 0.57–0.59). The model performed particularly well for forests with canopy heights between 10–40 m, though systematic biases were observed at the extremes of the height distribution. This framework demonstrates how freely available satellite data can be leveraged to extend the utility of limited LiDAR coverage, enabling cost-effective forest structure monitoring across vast tropical landscapes. The approach can be adapted to other forest regions worldwide, supporting applications in ecological research, conservation planning, and forest loss mitigation.

Natural Vacuum Solar Desalination technology was designed and built for one of solutions for water scarcity issues right now. An evaporator as the main part of this system should be analyzed to achieve a good result (fresh water productivity). The evaporator is used as an evaporation chamber to evaporate seawater which will be condensed to water storage. The commercial code CFD ANSYS Fluent 16.1 has been used to simulated and analyzed of heat and mass transfer inside the evaporator. There is no laminar model was used in this work with the temperature of heating coil was 70°C and the operation pressure was under atmospherical pressure. In this work, the results of simulation and experimental will be compared to be a validation. The highest temperature 72°C was in heating coil and the lowest temperature 38°C was in a body of evaporator based on the simulation result. The temperature of heating coil was increasing during evaporation processes. From these comparisons, shows there's a little discrepancy with a magnitude of error between 0,02% to 33%. It also shows the method has been used is right for analyzed and simulated about evaporation-condensation processes.

A field observation has been done to know Kandelia candel reproductive organs phenology, at Berbak and Sembilang National Park, South Sumatra, from November 2018 until January 2019. This study aimed to find out the phenology of the K. candel in South Sumatra. The results of this study showed that flower initiation occurred in April, mature from November to January; 290 days period is needed by flower initiation until the mature propagule.

By 2010, Sumatera Island of Indonesia had lost the highest annual forest cover due to oil palm ( Elaeis guineensis Jacq.) expansion, leading to adverse environmental impacts. The introduction of oil palm agroforestry (OPAF) within the social forestry program was to reduce these environmental impacts, conserve biodiversity, enhance wildlife habitat, and improve smallholder household resilience. However, the information on OPAF implementation progress and its benefits and ecological impacts still need to be explored. This research aims to measure the diversity of birds in young OPAF by comparing birds’ diversity in four land covers: young oil palm agroforestry (three years after establishment), old oil palm agroforestry (20 years after establishment), oil palm monoculture, and secondary forest. We indicated 43 bird species from 25 families across all land covers. The secondary forest had the highest valueof bird diversity index value of 2.80. The second was the first young oil palm agroforestry (2.42), followed by old OPAF, oil palm monoculture, and the second young OPAF with index values of 2.30, 2.19, and 2.16, respectively. Enrichment planting on oil palm monoculture through OPAF development could help restore tropical forests’ structural complexity while also providing more suitable bird habitats.